Phonologically Disordered German

Research
Phonologically Disordered German-Speaking
Children
Annette V. Fox
Barbara Dodd
University of Newcastle upon Tyne,
United Kingdom
Speech sound disorders affect more
children than any other developmental communication disorder and are associated with longterm social and academic difficulties. The
diversity of presenting symptoms has resulted
in the need for classifying subgroups of speech
disorders. Research on English-speaking
children suggests that there are four types of
surface speech error patterns (B. Dodd, 1995):
articulation disorder (e.g., lisp); delay (i.e.,
normal developmental patterns that are
inappropriate for chronological age); consistent
use of atypical error patterns (e.g., deletion of
all initial consonants); and inconsistent pronunciation of the same lexical items. Classification
typologies should be language independent.
This study investigated whether the same four
subgroups, in similar proportions, would be
found in German-speaking children who had
B
etween 3% and 10% of 4-year-old children have
disordered speech (National Institute on Deafness
and other Communication Disorders, 1994; Gierut,
1998). Children with speech sound disorders constitute
70% of patients referred for treatment by pediatric speechlanguage pathologists (Weiss, Gordon, & Lillywhite,
1987), and ASHA reports phonological disorders to be the
most prevalent pediatric communication disability
(www.asha.org, 2001). These children often produce so
many pronunciation errors that their speech is difficult or
impossible to understand. These intelligibility problems
can lead to difficulties in forming social relationships and
to low academic achievement. Difficulties in producing
speech can be persistent; the consequences are often
observable in adulthood (Lewis & Fairbairn, 1992). Mispronunciations by these children do not reflect young children’s
typical acquisition of speech in terms of rate of acquisition
or types of errors. Most importantly, children with speech
disorders are a heterogeneous group, differing in types of
surface speech error patterns (Dodd & McCormack, 1995),
severity (Garrett & Moran, 1992), etiology (Shriberg,
disordered speech. A total of 110 monolingual
German-speaking children, aged 2 years 7
months to 7 years 7 months, participated in the
study. They had been referred for assessment
of a suspected speech disorder. The results
supported the subgroup classification, providing
evidence for the universal character of speech
disorders. One significant difference was the
relatively high proportion of children classified
as having an articulation disorder. This was
explained by the uncertainty regarding a lisp as
a disorder in German, since it is also found in
up to 40% of normally developing children of
the same age. The theoretical and clinical
implications of the findings are discussed.
Key Words: phonological disorders, speech
disorders, German, classification system,
crosslinguistics
1982), and other associated language difficulties. In
addition, different children respond to different intervention approaches (Dodd & Bradford, 2000).
Because no single treatment technique is appropriate for
such a diverse population, there is a need for research to
evaluate methods of differentially diagnosing subgroups of
children with speech disorders. The development of costeffective intervention programs is dependent on the
validation of classification systems for speech disorder
(Dodd, 1993; Shriberg, 1982). Three classification methods have been predominant.
Medical-Etiological Approach
Medical diagnoses associated with speech and language
disorders include cerebral palsy, hearing loss, cleft palate,
and a number of syndromes such as Down syndrome
(Crystal & Varley, 1993). Although these conditions play
an important role in differential diagnosis, most children
with speech disorders do not present with a medical history
of this kind. Shriberg (1994) proposed a classification
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001 • © American Speech-Language-Hearing Association
Fox & Dodd: Differential Diagnosis of Phonological Disorders
1058-0360/01/1003-0291
291
system based on etiological factors that are often less
obvious: positive family history of speech, language, and/
or literacy difficulties; frequent middle ear infections;
developmental apraxia of speech; psychological involvement; and residual errors (isolated phone-distortions).
Unfortunately parents often report either none or more than
one of these conditions. Therefore, groups of children
remain unclassifiable. Further, lack of normative data
(Shriberg, 1993) raises the question of whether these
factors accurately differentiate children with speech
disorders from normally developing children.
Clinical-Inferential/Linguistic
Perspective Approach
A more successful approach to diagnosis has been the
clinical-inferential analysis of speech data, including an
examination of phonological error patterns. The classification approach relying on severity, the Percentage Consonants Correct measure (PCC; Shriberg & Kwiatkowski,
1982), is included in this category. Other researchers have
identified subgroups of children in terms of the characteristics of their surface speech error patterns. Three phonologically disordered subgroups have emerged: delay (Fletcher,
1990), consistent but unusual (nondevelopmental) errors
(Leonard, 1985), and inconsistent errors (Dodd & Leahy,
1989). Although assessment procedures should “provide
some framework for the identification of different types of
disordered pronunciation patterns in children” (Grunwell,
1985, p. 3), they fail to identify the deficit underlying
different types of disorder (Stackhouse & Wells, 1997).
Psycholinguistic Approach
Cognitive neuropsychological and psycholinguistic
models “view a child’s speech problem in terms of breakdowns in aspects of input processing, output processing and
internal representation” (Lambert & Waters, 1995, p. 97).
These models (e.g., Dodd, 1995; Stackhouse and Wells,
1997) promote hypotheses about the nature of the deficits in
perceptual, cognitive-linguistic, and motor skills that result in
different types of speech disorders (Holm, 1998). Psycholinguistic approaches to classification have the advantage of
identifying a deficit that can be targeted in treatment.
A study of 50 Australian-English-speaking children
(Bradford & Dodd, 1996) combined the clinical inferential/
linguistic and psycholinguistic approach. This study
suggested that speech disorders can be classified into four
subgroups in terms of surface error patterns that reflect
differing underlying deficits in the speech processing
chain:
1. Articulation Disorder: The consistent mispronunciation or distortion of a phoneme in isolation and in all
phonetic contexts resulting from an impairment of the
“processes involved in the planning and execution of
smooth sequences of highly overlapping gestures of the
speech organs” (Fey, 1992, p. 225) is classified as an
articulation disorder.
2. Delayed Phonological Development: “A classification of delayed phonological acquisition is warranted when
292
all phonological processes derived to describe a child’s
speech errors occur during normal development but are
typical of a younger chronological age level” (Dodd, 1995,
p. 55). A delay of 6 months has been suggested to be
significant (Crystal, Fletcher, & Garman, 1989).
3. Deviant-Consistent Phonological Disorder: Children
should be classified as having a deviant-consistent disorder
if at least one of the error patterns they use consistently is
nondevelopmental (i.e., an error pattern not observed
during normal phonological development) or occurs on
phonemes that are not affected by this pattern in normally
developing children. For example, in German, the error
pattern final consonant deletion (FCD) occurs in normally
developing children only on /t k l/ (Fox & Dodd, 1999).
FCD is idiosyncratic if it occurs on any other final consonant. “Most children who make nondevelopmental errors
also use some developmental error patterns that may, or
may not, be appropriate for their chronological age. They
should nevertheless be classified as having a ‘deviantconsistent disorder’, since the presence of unusual error
patterns signals an impaired understanding of their native
phonological system” (Dodd, 1995, p. 56).
4. Deviant-Inconsistent Phonological Disorder:
Children who do not consistently pronounce the same
lexical item in the same way in one-word elicited utterances are classified as having an inconsistent phonological
disorder. Children are included in this subgroup if their
inconsistency rate is greater than 40% on a specific test of
the same 25 lexical items produced on three separate trials
in one assessment session (Dodd, 1995). This is an
arbitrary criterion selected because normally developing
children (who have a vocabulary of more than 50 words)
show inconsistency of less than 10% (Teitzel & Ozanne,
1999). Children with phonological delay and deviantconsistent disorder show inconsistency of less than 30%
(Zhu & Dodd, 2000).
Three sources of evidence can be used to evaluate this
classification system. Subgroups must be able to be
differentiated by tasks evaluating perceptual, cognitivelinguistic, or motor skills. There should be evidence that a
specific intervention approach benefits a specific subgroup.
Finally, data should be sought to determine whether the
classification system has application across speechdisordered populations, including those that speak languages other than English. A brief overview of available
evidence follows.
Identifying Deficits In the Speech
Processing Chain
Experimental studies have compared subgroup performance on measures associated with speech processing. In
an initial validation of the three phonologically impaired
subgroups (Dodd, Hambly, & Leahy, 1989), the consistent
use of nondevelopmental error patterns in children was
attributed to an impaired ability to master the phonotactic
constraints of the phonological system to be acquired. This
subgroup of children performs more poorly than the other
subgroups on tasks assessing rhyme and alliteration
awareness, awareness of phonological legality, and literacy
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
measures (Dodd et al, 1989, 1995). This would seem to
reflect a cognitive-linguistic difficulty that lies at the
organizational level of the speech chain (Grundy, 1989).
This classification system has been further validated by
Leitão, Hogben, and Fletcher (1997, who observed the
same subgroups in their group of English-speaking
subjects with speech disorders. Children in the deviantconsistent subgroup were most likely to experience
difficulties in the acquisition of literacy.
In contrast, children who make inconsistent errors seem
to have an intact phonological system. A series of experiments indicated that children classified as inconsistent
perform as well as age-matched, normally speaking
controls on tasks assessing phonological awareness (Dodd
et al., 1989), yet they perform poorly on tasks assessing
expressive lexical measures (Dodd & McCormack, 1995)
and phonological assembly tasks (Bradford-Heit, 1996).
No deficit in the speech processing chain has yet been
identified for the articulation-disordered and delayed
subgroups in the preschool years. They performed within
normal limits on most experimental tasks, albeit at the
lower end of the normal range (Dodd & McCormack,
1995).
Intervention Specificity
Experimental studies allow hypotheses concerning the
aspect of the phonological processing chain that should be
the focus of intervention for two subgroups: the metaphonological skills of children who consistently use
atypical phonological error patterns, and phonological
assembly for children who make inconsistent errors. The
results of treatment case studies have provided initial
evidence that supports these hypotheses. An alternative
treatments clinical research design revealed that children
with consistent nondevelopmental errors benefited most
from treatment targeting phonological contrasts, whereas
use of a core vocabulary increased both speech accuracy
and consistency of children making inconsistent errors
(Dodd & Bradford, 2000).
Two other studies evaluated the efficacy and generalization of specific treatment approaches, in English, for
speech disorder in bilingual children in order to test
hypotheses about the nature of the underlying deficits
(Holm & Dodd, 1999; Holm, Ozanne, & Dodd, 1997). It
was predicted that treatment targeting phonological
contrasts should not generalize because phonological
contrasts are language specific, whereas a core vocabulary
approach to inconsistency should generalize because
phonological assembly is a mental process common to both
languages. Although phonological contrast treatment
resulted in remediation of cluster reduction in English, there
was no generalization to [k(h)w] in Cantonese. In contrast,
core vocabulary treatment in English generalized to
Punjabi in a child who was inconsistent in both languages.
Crosslinguistic Studies
Most research on phonological disorder has focused on
monolingual English-speaking children. Crosslinguistic
description should allow evaluation of classification
systems for speech disorder as well as data concerning the
effect of the ambient phonology on disorder. Studies of
speech disorders have been conducted for children
speaking other languages including Italian (Bortolini &
Leonard, 1991), Portuguese (Yavas & Lamprecht, 1988),
Swedish (Nettelbladt, 1983), Cantonese (So & Dodd,
1994), Turkish (Topbas & Konrot, 1996), Spanish
(Goldstein, 1996), and Putonghua (Zhu & Dodd, 2000). In
general these studies suggest that some error patterns
occur in most languages whereas others are languagespecific. Only the last four studies evaluated whether the
classification system for English, proposed by Dodd
(1995), is applicable to other languages. All four studies
provided support for the subgroup classification. The four
subgroups were identified in Cantonese, Putonghua, and
Turkish. Goldstein (1996) identified only three of the
groups, finding no children who made inconsistent errors.
However, he did not test for consistency of production of
the same lexical items. Given that previous studies have
focused on small numbers of children (4–33), there is a
need for larger studies of speech disorder in languages
other than English.
The primary purpose of the study reported here was to
investigate whether the four hypothesized subgroups of
speech disorders (Dodd, 1995) could also be found in
German, as a second Germanic language, in a large-scale
study. These data would provide evidence concerning the
validity of the classification approach as well as the
universal nature of developmental speech disorders. Of
particular interest was whether the proportions of children
classified as having articulation disorder, delay, consistent
use of nondevelopmental error patterns, and inconsistent
production of the same lexical items were similar across
languages.
German Phonology and Variations
in Northern German
German belongs to the Germanic languages and is the
first language of approximately 119 million people in 15
countries, with the largest communities in western and
central Europe. German is the official state language in
Germany, Austria, and parts of Switzerland, Liechtenstein,
and Luxembourg (Barbour & Stevenson, 1990; Durell, 1992;
Lyovin, 1997). There are regional variations in pronunciation, from accents to dialects, of the official language
(Hochdeutsch), that is based on a North German pronunciation of the written language (Barbour & Stevenson,
1990; Durell, 1922; Goltz & Walker, 1961). The spelling
of standard German generally gives a clear guide to
pronunciation.
High German contains 23 consonant phonemes /p b t d
k g f v s z S x C h m n N l ‰ j / pf ts/. The glottal stop ///
appears before syllable initial vowels and is compulsory.
The sounds /pf/ and /ts/ will be treated as affricates
following Ternes (1987), and not two-element clusters
despite disagreement in the literature (Kohler, 1995;
Ternes, 1987; Wiese, 1996). Whether /C/ and /x/ should be
considered as two phonemes or as allophones is also
Fox & Dodd: Differential Diagnosis of Phonological Disorders
293
controversial (Kohler, 1995; Si-Taek 1992; Wiese, 1996),
but for ease of presentation they will be classified as
phonemes. In word-final position the contrast between
voiced and voiceless consonants is neutralized, with all
consonants being voiceless. In word-initial position there
are 22 two-element clusters and 2 three-element clusters.
There are also many word-medial and word-final clusters.
The vowel system contains 15 monophthongs (see Table 1)
and 3 diphthongs, which, in the North, have a tendency to
be over-stressed (Lenisierung).
The shortest possible syllables are the structures CV,
e.g. /ku…/ = Kuh (cow), and VC, e.g. /ap/ = ab (off).
Structures of the combinations C1-3VC1-5 in monosyllabic
words are possible: C1-3, e.g., /St‰/ in Strumpf (sock);
C1-5, e.g., /mpfst/ in du schrumpfst (you shrink). German is
an agglutinating language where, by addition of nouns,
words can consist of about eight syllables or more, e.g.,
TABLE 1. German and English phonology.
Englisha
German
pbtdkg
mn
fvzS‰h
j
l
ts pf
pbtdkg
mnN
f v s z S C xb ‰
l
ts pf
Initial Consonants
pbtdkg
mn
TDfvszSZh
wj
lr
‰¸
Medial Consonants
pbtdkg
mnN
TDfvszSZ
lr
‰¸
Final Consonants
pbtdkg
mnN
TDfvszSZ
lr
‰¸
ptk
mnN
fsSCx
l
ts pf
b p g k f pf + l
bpdtgkf+‰
k+n/v
ts + v
S+lmnp‰vt
S+p/t+‰
Word Initial Clusters
p g k f+l
bpdtgkfST+r
b p d t g k m n f v ‰ T+j
d t g k T+w
s+ptk m f l wj
s+p+l
s+ptk+r j
s+k+w
iye„ouIY”ŒaÁE
aI au OI (eå Oå uå)
Vowels
i I ” œ Ø a Å O u Á ∏E
Diphthongs
eI oÁ aI aÁ OI IE ”E OE ÁE
Syllable Structure (Monosyllables)
[C 0-3] - V- [C 0-3] nouns
[C 0-3] - V- [C 0-4]
[C 0-3] - V- [C 0-5] verbs
a
Data concerning British English are from Modern English
Structure by Strang (1969).
b
/C/ and /x/ are treated as two phonemes.
294
Hallenhandballweltmeisterschaft (indoor handball world
championship) (Meinhold & Stock, 1980).
All children taking part in this study grew up in the
region of Southern Schleswig-Holstein and Hamburg.
None of the parents or the children spoke North Saxon or
any other dialect, but they all displayed influences of the
North German accent. Variations in the use of consonants
in this region have been described by Goltz & Walker
(1961), Durell (1992), Barbour & Stevenson (1990), and
Kohler (1995).
The sound /r/ is always realized as [‰]. In all positions
other than before vowels, /‰/ is realized as a vocalic
Ersatzlaut (substitution sound) [å]. This creates several
additional long or short diphthongs as in Wurst [vu…åst]
(sausage) or Berg [be…åk] (mountain). The phoneme /N/ in
word-final position can be pronounced as either [N] or [Nk].
The consonant /l/ before /C/, as in Milch /milC/ (milk), may
be deleted and the vowel changed to [e]. The final letter
“g” can be pronounced as either [k] or [C]. In word-initial
position the affricate /pf/ may be replaced by [f] and the
cluster /pfl/ may be replaced by [fl]. The replacement of
/pf/ by [f] has been recorded as a phenomenon that is very
common in colloquial speech (Barbour & Stevenson, 1990)
and in the North (Durell, 1992). Further, the deaffrication
of /ts/ to [s] in word initial position has been described as
common. Replacement is unlikely to cause problems in
understanding, since /s/ stays contrastive with /z/ in word
initial position and no homonyms are created. The wordfinal unstressed syllables /En/ and /El/ can be reduced and
assimilated, i.e., [ge…bm] instead of /ge…bEn/ geben (to
give), and [fo…gl] instead of /fo…gEl/ Vogel (bird).
Speech Treatment Provision and
Phonological Disorders
In the German literature, speech disorders are referred
to as “articulation disorder” or “dyslalia” and sometimes
even “Stammeln” (stammer). The distinction between
phonological and phonetic disorders was initially described
by Scholz (1974), and more recently by Dickmann et al.
(1994), Böhme (1998), and Hacker and Wilgerstein (1999).
However, speech disorders are still classified primarily
according to severity, etiology, or co-existing symptomatology (Wirth, 1990; Biesalski & Frank, 1994; Böhme,
1997). Treatment is typically based on articulation treatment approaches (e.g., Van Riper, 1963) and more recently
approaches based on translations of English work (e.g.,
Metaphon: Jahn, 2000). Consequently, research needs to
establish whether diagnostic categories developed from
research on English-speaking children are applicable to
monolingual German-speaking children.
Two studies have assessed the distribution of phonological processes in children with speech disorders. Hacker
and Weiss (1986) studied fifteen 5- to 7-year-old children
with speech disorders. Most errors were substitutions, 9%
were deletions, and 4% were assimilation errors. The
processes most frequently identified were cluster reduction,
fronting, stopping, and backing. Although this study sought
to identify delayed or deviant acquisition, this could not be
achieved since normative data were limited.
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
Romonath (1991) assessed 35 children aged 5;3–7;2
(years;months) and compared the number and types of
phonological processes of children with speech disorders
with those of an age-matched, normally developing control
group. Children with speech disorders used a greater
number of processes, and 25% of their processes did not
occur in the speech of normally developing children of the
same age. Processes occurring frequently were velar
fronting, backing of consonants, prevocalic voicing,
alveolar assimilation, stopping of liquids, obstruent
devoicing, cluster reduction, and final consonant deletion.
Möhring (1938) investigated the vulnerability to error of
each phoneme of German in 1000 children aged 6–10
years. He described a hierarchy of difficulty according to
their percentage of incorrect production. Three groups of
different difficulty level were identified:
1. 1.5%–11.1%: m, n, b, d, p, l, t, f, v
2. 17.9%–28%: x, j, ‰, N, k, g
3. 33.5%–54.5%: C, S, s/z
There are three hypotheses for this study:
1. German-speaking children with speech disorders can be
classified according to four subtypes based on their
surface error patterns: articulation disorder, delay, atypical
error patterns, and inconsistent errors. This hypothesis is
based on the assumption of the universal nature of
speech development and its disorders. The data will
provide evidence concerning the validity of the classification procedure and the assumption of universality.
2. The proportion of children classified as falling into each
subgroup will be similar to results for other languages
(Cantonese, English, and Putonghua).
3. Differences in the use of phonological processes among
German, English, and other languages should be found,
since the phonetic inventory and phonological constraints of the languages differ. In particular, since there
is no contrast between /T/, /D/ and /s/, /z/ in German,
German-speaking children might show a different error
pattern from English-speaking children. Since English
and German belong to the same language family, other
differences should be minimal.
Method
Subjects
A native German speech-language pathologist (AF)
tested 110 children between the ages of 2;7 and 7;7. These
children had been referred to speech and language treatment because of concerns about their speech. Most
children (N = 79) were on the waiting lists at two private
practices in Northern Germany and were randomly chosen
for an appointment for this study by the speech-language
pathologists of the practices. Preschool teachers referred
31 children to the study during the collection of data on
normal speech development in kindergartens. Criteria for
participation in the study were: (a) age between 2;6 and
8;0; (b) referral for assessment of suspected speech
disorder; (c) no previous treatment; (d) no sensory
impairment, organic motor disorder, cranio-facial anatomical anomaly, or intellectual impairment; (e) monolingual
German speaker; and (f) no hearing loss detected at
assessment. Based on these criteria, 100 children proved to
be suitable for the study. A total of 10 children were
excluded: 1 child did not speak, 2 children named too few
pictures to obtain an adequate speech sample, and 7
children no longer evidenced speech problems. There were
63 boys and 37 girls in the population. This proportion of
around 2:1 is reported to be commonly found in children
with speech and language difficulties (Romonath, 1991).
Procedure
The children were assessed individually in a single
session at the private practice to which they had been
referred. The assessment took place in a quiet room with
only the tester, the child, and the mother (or parents)
present. The session consisted of three parts: assessment
tasks, free play, and parental advice. The whole session
was recorded on audiotape using a Sony Professional
Micro Stereo Recorder for a second phonetic transcription
of the assessment. During the assessment the mothers were
asked to complete a questionnaire about the child’s
developmental and medical history and to give their
permission for anonymous use of all data in the study. At
the end of the session the mothers were informed whether
treatment was indicated and were advised about how to
deal supportively with the speech and language problem in
daily communication.
All children underwent the following assessments:
1. Single-Word Test: A picture-naming assessment
procedure (Single-Word Test) was used to elicit data. The
assessment included 99 items assessing all German
phonemes in all possible word positions, as well as most
word initial clusters and a sample of word medial and final
clusters (see Appendix A). The task was identical to that
used for our normative study (Fox & Dodd, 1999). The
objective was to investigate the child’s phonetic and
phonemic inventory and to derive the phonological
processes used. The children were asked to name the
pictures presented and were offered a sentence completion
task in case of difficulty. If this help was insufficient, they
were offered a choice of possible answers. Direct imitation
was avoided.
2. The 25-Word Consistency Test: A German version of
the 25-Word Consistency Test (Dodd, 1995) was created.
It is a picture-naming task containing words of up to five
syllables, with many consonant clusters or words that are,
from clinical experience, difficult for German-speaking
children to produce. Children were asked to name the
pictures on three separate occasions within one assessment
session, each occasion being separated by another activity.
The words of this assessment can all be found in the
Single-Word Test. Each child was asked to repeat these 25
words twice more throughout the session, either as a
straightforward picture-naming task or integrated in a
game, depending on the child’s age and cooperation. The
word list can be found in Appendix B. This task was
carried out to determine whether the child was consistent
Fox & Dodd: Differential Diagnosis of Phonological Disorders
295
in his pronunciation of phonemes in an identical phonetic
context, when producing single words.
Analyses
Using the International Phonetic Alphabet Revised
(1993), the examiner transcribed all utterances made by the
child. The picture-naming tasks were transcribed online
during the session, and again later from tape. Intrarater
(point-to-point) reliability on data from 10% of the
children randomly chosen for transcription reliability
assessment (the picture naming task, the inconsistency
task) was 95%. Additionally, 10% of the data were chosen
randomly to assess reliability of phonetic transcriptions of
two examiners; both spoke German as a first language, and
one was a phonetician. The interrater reliability of broad
phonetic transcription for consonants and vowels (as
suggested by Shriberg, Lewis, McSweeny, & Wilson,
1997) was 96.2%.
The criteria for classification into subgroups were strict
and based on the Single-Word Test and the 25-Word
Consistency Test. To be classified as being delayed, all of
the child’s error patterns had to be identified as being used
by at least 10% of children in the normative sample (Fox &
Dodd, 1999) sometime during development between 18
months and 6 years. At least one of those error patterns had
to be inappropriate for the child’s chronological age, being
typical of an earlier stage of phonological development. To
be classified as belonging to the deviant-consistent subgroup,
a child had to consistently use at least one error pattern that
was not used by more than 10% of children in the normative sample (Fox & Dodd, 1999) at any age. To be classified as inconsistent, a child had to realize at least 40% of
words in the 25-Word Consistency Test differently over
three trials (i.e., where all three productions differed, or
one production differed from the other two that were the
same). Two speech-language pathologists, a native German
fairly unfamiliar with the procedure and an Australian who
regularly uses the classification system in clinics, were
asked to independently classify 20% of the children
randomly chosen out of the 100 subjects. The classification
reliability was 94.7%.
Each child’s transcript was analysed to derive the
following measures:
Phonetic Repertoire: A phone was accepted as being
part of a child’s phonetic inventory if it was correctly
realized at least twice within the data elicited from the
Single-Word Test, irrespective of whether the sound
uttered was phonologically correct.
Phoneme Repertoire: A phoneme was accepted as being
part of a child’s phonemic inventory if it was produced
correctly at least 66.7% of the time (on two out of three
occasions) within the picture-naming task data.
Percent Phonemes Incorrect (PPI): The percentage of
incorrect phonemes was calculated by multiplying the
number of incorrect phonemes by 100 and dividing by the
total number of phonemes produced within the SingleWord Test.
Inconsistency Score: An inconsistency score was
derived by calculating the number of trials where a word
296
was not produced identically on all three opportunities,
multiplying by 100, and dividing by the number of trials
(out of 25) where a word was attempted on all three
opportunities. Only spontaneous productions of the target
word were included in the analysis. For example, if the
target Hund was produced once correctly, once with initial
consonant deletion, and once with cluster reduction, it
would count as an inconsistent trial, as would an example
where Hund was produced once with initial consonant
deletion and twice with cluster reduction.
Number of Processes: A process was counted as present
if it occurred more than twice in different lexical items of
the Single-Word Test.
All measurements taken for this analysis were identical
to those outlined in our study of normal phonological
development in 180 monolingual children acquiring
German at ages 1;6–6;0 (see Appendices C1 and C2; Fox
& Dodd, 1999). This study was based on the same SingleWord Test. Children were classified into the four subgroups with reference to the normative data for phonological process use and their score on the 25-Word Consistency Test.
Results
The data were inspected to determine whether the
subgroups—articulation disorder, delay, deviant-consistent,
and inconsistent—were apparent. As shown in Table 2, 20
children (20%) were classified as having an articulation
disorder, distorting the sounds /s/, /z/, /C/, and /S/; 51
children (51%) were classified as having delayed phonological development; 17 children (17%) were classified as
having a deviant-consistent phonological disorder; and 12
children (12%) were classified as having an inconsistent
phonological disorder. Individual data for all children
using consistent error patterns can be found in Appendix
D. Table 3 gives an overview of the children in each
subgroup, their error pattern usage, mean inconsistency
percentage, percent phonemes incorrect (PPI), and their
mean number and types of missing phones and phonemes.
Articulation Disorder
Children who consistently distorted one or more
particular phonemes in all phonetic environments, but
made no other errors, were classified as having an articulation disorder. There were 7 girls and 13 boys, aged
between 4;8 and 7;8 (mean age 5;9), in the articulationdisordered group. An incomplete phonetic inventory is the
main feature of this disorder since children consistently
produced a speech sound to mark a particular phoneme, but
the sound produced was not a perceptually acceptable
version of the target sound. Of these 20 children, 19 replaced
/s/ and /z/ with [T] and [D] and /ts/ and [tT], 1 child replaced
these phones by a lateral [s], and 4 children lateralized the
phone /S/ (see Appendix D, Table D1). The distortions
identified were interdental and lateral production of sibilants.
The percentage of distorted phonemes (when counted as
incorrect) was between one and two standard deviations
above the mean for normally developing age-matched
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
TABLE 2. Subject information.
Articulation
Delay
Consistent
Inconsistent
Total
20
4 (4.8%)
51
51 (61%)
17
17 (20.2%)
12
12 (14.3%)
100
84 (100%)
No. of children additionally classified as
articulation disordered
N/A
29
10
6
No. of children additionally classified as
articulation disordered excluding interdentalitya
as a symptom for articulation disorder
N/A
5
1
0
No. of boys
13
31
12
7
No. and % of children
No. and % of children when isolated
/s/ and /z/ distortions are excluded
63
No. of girls
7
20
5
5
37
Mean age
5;9
5;1
4;9
4;2
5;0
a
Because of findings by Fox & Dodd (1999), interdentality may be a variation of the norm rather than an indication of articulation disorder.
Therefore, numbers of children with and without interdentality are presented.
children (see Figure 1). No children in this group showed
an incomplete phonemic inventory (since the phoneme was
marked consistently, although distorted). Their inconsistency rating was 0%.
Interdental production of sibilants does not necessarily
merit a classification of articulation disorder since the
normative sample (Fox & Dodd, 1999) indicated that
interdental production might be considered allophonic (see
Discussion). Tables 2 and 5 therefore present data for the
articulation-disordered group in two parts: including all
children initially identified as being articulation disordered
and excluding the 16 children whose only speech difficulty
was interdental production of sibilants. Excluding these
latter 16 children reduces the percentage of articulation
disorder to 5%.
Delay
A total of 51 children (22 boys and 19 girls), aged
between 3;3 and 7;9 (mean age 5;1), were classified as
delayed. The percentage of incorrect phonemes was
between one and two standard deviations above the mean
for normally developing age-matched children, but for
children older than 5;3 years, it increased to two to four
standard deviations above the age-matched appropriate
mean (see Figure 2). When the phones /s/, /z/, and /ts/ were
included, 37 children (73%) showed an incomplete
phonetic inventory, but only 26 (51%) did so when these
phones were excluded. Apart from /s/, /z/, and /ts/, the
main missing phones were identical to the missing phonemes. Thirty-five of the delayed children (69%) showed
TABLE 3. Information about subgroup results.
Articulatory error patterns
Articulation
Delay
Consistent
★
★
★
★
★
★
N/A
★
N/A
59%
Developmental error patterns
Idiosyncratic error patterns
Inconsistent
Mean inconsistency
0%
13%
19%
Mean no. of error patterns
1.15
2.55
5.06
N/A
Range of error patterns
1–2
1–7
3–10
N/A
22%
Mean PPI
7%
9%
19%
Mean z-score PPI
1.89
0.74
3.98
3.97
Mean PCI
10%
14%
29%
35%
Mean no. missing phones
2.05
1.9
3.6
2.25
s/z ts S
s/z ts S g k N
s/z ts S C ‰
t d n pf
s/z ts S ‰ pf
vx
Mean no. missing phonemes
0
1.72
4.29
4.75
Standard deviation of missing phonemes
0
1.64
2.7
3.7
SgkN
S ts s/z C f v
pf d t n k g ‰
All but
mnNpbC
Most frequently missing phones
Most frequently missing phonemes
Note. PPI = percentage phonemes Incorrect; PCI = percentage consonants incorrect.
Fox & Dodd: Differential Diagnosis of Phonological Disorders
297
TABLE 4. Comparison of two studies ranking phonemes according to the percentage of children
producing a specific phoneme incorrectly.
Most correct
Möhringa
This study
a
m n h b d p l t f v
m b p l h n j x d t v pf
Least correct
x j ‰ N k g
f N C ‰ g k S
C S s/z
s/z* ts*
Möhring (1938) does not present data for /ts/, /pf/ and /h/.
* /T/ and /D/ were accepted as correct allophonic variations of /s/ and /z/.
an age-inappropriate phonemic inventory, with a mean of
1.72 (SD 1.6) missing phonemes per child (usually /k/, /g/,
/N/, /C/, or /S/). The mean inconsistency rate for this group
was 13%. The error patterns of the children classified as
delayed had to reflect normal development but inappropriateness for chronological age. The most common delayed
processes were cluster reduction, fronting of plosives and
sibilants, and interdentality as an additional articulatory
distortion (see Table D2).
Phonologically Disordered—Deviant-Consistent
A total of 17 children, 12 boys and 5 girls aged 3;5–6;11
years (mean age 4;9), were classified as having a deviantconsistent disorder. Their mean inconsistency rate was 19%
and the mean PPI was 19%. Although this mean percentage
was high, there was considerable individual variation:
although some children’s PPI was only one or two standard
deviation above the mean for normally developing children,
FIGURE 1. Percentage phonemes incorrect (PPI) for articulation disorder.
FIGURE 2. PPI for delayed phonological development.
298
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
TABLE 5. Crosslinguistic comparison of the distribution of subgroups according to Dodd’s classification system (1995).
No. of children
Articulation
Delay
Deviant
Inconsistent
English
Cantonese
Putonghua
Spanish
55
14%
58%
12%
16%
17
12%
47%
29%
12%
33
3%
55%
24%
18%
20
10%
65%
25%
—b
Germana
100
20%
51%
17%
12%
84
5%
61%
20%
14%
Note. English (Dodd, 1995); Cantonese (So & Dodd, 1994); Putonghua (Zhu & Dodd, 2000b); Spanish
(Goldstein, 1996).
a
The left column indicates the number and percentage of children including children with an isolated lisp,
whereas the right column presents data excluding these children.
b
Not assessed
others reached a PPI of six to eight standard deviations
above the mean (see Figure 3).
Fourteen children (82%) showed an incomplete phonetic inventory, and 15 children (88%) showed an incomplete phonemic inventory. Unlike results for the delayed
group, there were no phones or phonemes (excluding /s/,
/z/, and /ts/) that were particularly affected. Missing
phonemes (that should have been acquired) in four to
seven of the children were /d/, /t/, /n/; /f/, /v/, /pf/; /s/, /ts/,
/C/; k/, /g/, and /‰/. All children showed developmental
error patterns as well as idiosyncratic ones. Furthermore,
some children used a very unusual pattern of cluster
reduction and were therefore classified as deviantconsistent disordered. The most common developmental
and idiosyncratic processes were: fronting, backing of
plosives, /f/ → [s] or [T], and cluster reduction. Interdentality as an articulatory phenomenon was also common
(see Table D3).
Inconsistent
A total of 12 children, 7 boys and 5 girls aged 2;7–5;8
(mean 4;2), were classified as inconsistent. The mean
inconsistency rate was 59%. A one-way ANOVA comparing the rates of inconsistency between the four subgroups
demonstrated that significant differences could be found:
F(3, 96) = 52.336, p < .001. Post-hoc analysis using
Student-Newman-Keuls showed that the inconsistent
disordered group was significantly different from all other
subgroups. The same was found for the articulationdisordered group, which was highly consistent. No
significant differences were found between the delayed
and the deviant-consistent phonologically disordered
subgroups.
The mean PPI in the inconsistent disordered group was
22%, the highest of all groups (see Figure 4). Nine children
showed incomplete phonetic and 10 showed incomplete
phonemic inventories. However, if the phones /s/, /z/, and
/ts/ were excluded, only 7 children (58%) showed incomplete inventories, with fewer phones than phonemes
missing. The most vulnerable phonemes were /k/, /‰/, /f/,
/v/, /x/, and /pf/. Since the main feature of these children is
inconsistency, error pattern descriptions will reflect only
that one assessment and will differ on reassessment. Ball
(1994) therefore argues that it is inappropriate to analyze
inconsistent errors for phonological processes.
FIGURE 3. PPI for deviant-consistent phonological disorder.
Fox & Dodd: Differential Diagnosis of Phonological Disorders
299
FIGURE 4. PPI for inconsistent phonological disorder.
Group Comparisons
Figures 1–4 show the distribution of the percent
phonemes incorrect (PPI) for each child in each subgroup.
Each child’s PPI was compared to the mean PPI z-scores
obtained from the normative study (Fox & Dodd, 1999). A
child’s PPI was compared to the z-scores of the appropriate
normative age group. Two comparison data points are
shown: the normative mean PPI z-scores, and that point
plus two standard deviations.
A one-way ANOVA comparing the PPIs of the four
subgroups revealed significant differences: F(3, 96) =
31.772, p < .001. Post-hoc Student-Newman-Keuls showed
no significant differences between the articulation disordered
and delayed groups or between the deviant-consistent
phonologically disordered and inconsistent phonologically
disordered subgroups. The articulation disordered and
delayed subgroups were significantly different from both
the phonologically disordered subgroups.
Comparisons with Previous German
Language Research
Comparison of current results with those of previous
studies (Hacker & Weiss, 1986; Romonath, 1991) reveals
general agreement. The common error patterns identified
were initial and final consonant deletion, weak syllable
deletion, cluster reduction, assimilation, metathesis,
fronting, backing, stopping, voicing, and devoicing. Other
error patterns described were less frequent and idiosyncratic. The hierarchy of phoneme/phone difficulty as
described by Möhring (1938) was also supported apart
from the positions of the fricatives /C/ and /x/ and the
approximant /j/ that appeared to be less vulnerable in our
study (see Table 4) and the fricative /f/, which appeared
more vulnerable in our study.
Crosslinguistic Comparison of Classification
The distribution pattern (percentages per subgroup) for
English, Putonghua, and Cantonese was similar across all
300
languages assessed, as shown in Table 5. The small
number of Turkish-speaking children assessed (N = 10) did
not allow the presentation of distribution percentages (Topas
& Konrot, 1996). For German, two types of percentages are
presented. The left column shows the percentages of all 100
children assessed, while the right column shows the distribution percentage when 16 children with an isolated interdental /s/ production are excluded.
Speech error types across languages are compared in
Table 6, which lists descriptive characteristics and most
common error patterns for subgroups in German, English,
Putonghua, and Cantonese. The most frequent individual
error patterns found in each language depend on the phonological system of that language, but there are similarities. The
most common delayed error patterns reported were cluster
reduction, velar fronting, and stopping, whereas the most
frequently reported nondevelopmental error patterns were
backing and intrusive consonants. The data from all four
languages indicate the following hierarchy for segmental
errors across the four subgroups: articulation disorder <
delay < deviant-consistent < inconsistent.
Discussion
Crosslinguistic research provides evidence concerning
the validity of classification systems for speech disorders.
As previous studies have shown for Cantonese, Turkish,
Spanish, and Putonghua, this study of German-speaking
children has further supported Dodd’s (1995) classification
of speech disorders based on English-speaking children.
The four subgroups: articulation disorder, delay, and
deviant-consistent and inconsistent phonological disorder,
were apparent in 100 German-speaking children referred to
speech and language treatment for assessment of a suspected speech disorder.
Twenty children (20%) were classified as having a
specific articulation disorder, which is high in comparison
to other languages studied. There are two possible reasons
for the finding. Data for this study were collected only in
private practices and kindergartens. Children with an
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
TABLE 6. Crosslinguistic comparison of the subgroups.
German
English
Cantonese
Putonghua
Stopping
Deaspiration
Final consonant
deletion
Final glide
deletion
Cluster reduction
Stopping
Gliding
Fronting of
sibilants
Affrication
Most frequent developmental error pattern
Interdentality
Fronting of
plosives
Fronting of
sibilants
Cluster reduction
Fronting of /N/
Cluster
assimilation
Final consonant
deletion
Cluster reduction
Weak syllable
deletion
Reduplication
Fronting of
velars
Stopping
Most frequent idiosyncratic error pattern
Backing of
alveolars
/f/ → /s/ or /T/
Metathesis
Intrusive
consonants
Consonant
deletion
Allophonic
fricatives
Favorite sound
Cluster changes
Backing
Backing
Initial consonant Vowel rule
deletion
Medial
consonant
deletion
Intrusive
consonants
Medial consonant
substitution
Denasalization
Favorite sound
Backing and
stopping
Final consonant
addition
Vowel change
Mean no. of missing phones: articulation
Mean no. of missing phones: delay
Mean no. of missing phones: deviant-consistent
Mean no. of missing phones: inconsistent
2
1.9
3.6
2.25
no data
no data
no data
no data
1
3.5
2.4
1
1
1.6
2
6.3
Mean no. of missing phonemes: articulation
Mean no. of missing phonemes: delay
Mean no. of missing phonemes: deviant-consistent
Mean no. of missing phonemes: inconsistent
0
1.72
4.29
4.75
no data
no data
no data
no data
0
5
3
6
0
3.3
3.8
10.7
Mean PCI: articulation
Mean PCI: delay
Mean PCI: deviant-consistent
Mean PCI: inconsistent
10%
14%
29%
35%
no data
23%
46%
69%
10%
22%
24%
29%
7%
15%
26%
39%
Mean no. of developmental error patterns: delay
Mean no. of idiosyncratic error patterns: delay
Mean no of developmental error patterns: deviant-consistent
Mean no. of idiosyncratic error patterns: deviant-consistent
2.55
0
1.6
2.2
2.7
0
3.5
1.9
3
0
0.4
2.8
1.6
0
1.25
1.5
Mean inconsistency: articulation
Mean inconsistency: delay
Mean inconsistency: deviant-consistent
Mean inconsistency: inconsistent
0%
13%
19%
59%
no data
20%
24%
62%
no data
no data
no data
no data
14%
23%
25%
58%
Note. English: Bradford & Dodd (1996); Cantonese: So & Dodd (1994); Putonghua: Zu & Dodd (2000).
articulation disorder are usually referred to a private
practice because the disorder does not have priority for
assessment or treatment in public clinics. Data for the other
languages were collected in hospitals or outpatient clinics.
Thus, sampling may explain the difference in distribution
of articulation disorders. An alternative explanation is that
parents are more likely to seek treatment for a lisp in
Germany than in other cultures.
However, the phones /T/ and /D/ are not part of the
German phonetic inventory and the study of typically
developing children up to the age of 6;0 showed that 35%
of the children in the oldest age group used /T/ and /D/
consistently as allophones of /s/ and /z/ (Fox & Dodd, 1999).
The question then arises as to whether the interdental
production of the phonemes /s/ and /z/ really describes an
articulation disorder, or whether this kind of replacement
now needs to be accepted as a normal variation. If the latter
is true, 16 of these 20 children would need to be excluded
from our study, leaving only 5% of children with an
articulation disorder, which is similar to the findings for
English (14%), Putonghua (3%), Cantonese (12%), and
Spanish (10%).
A total of 51 children (61% after exclusion of the 16
articulation-disordered children with an interdental lisp)
were classified as showing delayed phonological acquisition. This percentage is similar to findings for all other
languages reported. These children used developmental
error patterns typical of a younger child. Some children’s
Fox & Dodd: Differential Diagnosis of Phonological Disorders
301
speech error patterns were chronologically mismatched, a
finding also reported by Grunwell (1987) and So and Dodd
(1994). The majority of children in this category presented
a speech delay of 6 to 9 months, although some children
showed delays of more than 18 months. This finding raises
a question concerning the clinical implications of the
extent of delay. Given that delay is the largest subgroup,
research is needed to address this question.
Seventeen children (20.2% after exclusions) were
classified as having a deviant-consistent phonological
disorder, a percentage consistent with other languages. As
expected, all children showed three types of processes: ageappropriate developmental processes, age-inappropriate
developmental processes, and nondevelopmental, idiosyncratic processes (see Tables 3 and 6). Although the
presence of some normal developmental error patterns is
positive, the consistent use of idiosyncratic error patterns
that restrict syllable structure (all final consonants deleted,
not just /t k l/) and reduce a class of consonants (e.g.,
plosives) to one phoneme (e.g., [k]) cannot be adequately
described in terms of severity or delay. These nondevelopmental speech error patterns indicate phonological processing difficulties that impair the ability to deduce the
constraints of spoken phonology and the orthographic
representation of speech sounds (Leitão et al., 1997).
Twelve children (14.3% after exclusions) were classified as inconsistent, similar to findings for other languages. These children represent the youngest age mean
of all subgroups, a finding also made for Putonghua (Zhu
& Dodd, 2000). There are two possible explanations.
Ingram (1989) argues that very young children (vocabularies of up to 50 words) show an inconsistent pattern of
word production, and that inconsistency is therefore a
normal part of the acquisition process. Since these
children represent the youngest age group, their inconsistency might reflect very severe delay. However, children
who make inconsistent errors do not have small phonetic
repertoires typical of very young children. Further, Teitzel
and Ozanne (1999) found that even very young children
(aged 20–24 months) show a very consistent pattern of
word production.
Alternatively, the younger mean age of the inconsistent
group might reflect their unintelligibility. These children
are often unintelligible even to their parents, who cannot
acquire knowledge of how particular words are pronounced, and might therefore refer children who make
inconsistent errors earlier. Data from the other subgroups
provide some support for the suggestion that degree of
unintelligibility affects the age at which children are
referred. Children with an articulation disorder are usually
intelligible, and this subgroup had the highest mean age
(5.9 years, with the youngest child aged 4.8 years).
Similarly, children in the delayed subgroup, who make
fewer errors than the two disordered groups, had a mean
age of 5.1 years. The argument that it is the type of errors
that is important, rather than the absolute number, is
emphasized by comparison of the two disordered groups.
Although these two groups had similar PPI z-scores (3.98
and 3.97), the inconsistent group had a younger mean age
(4.2 years). Parents with children who consistently make
302
the same errors (mean age in the current study, 4.9 years)
learn to translate. Inconsistency makes such translation
impossible and is likely to increase parental anxiety.
As mentioned in earlier studies, some children show an
articulation disorder in addition to a phonological delay or
disorder (Dodd & Bradford, 2000). So and Dodd (1994)
described two children with deviant-consistent disorder
who also had an articulation disorder. In this study, five of
the children who were classified as being delayed and one
child classified as deviant-consistent disordered, were
additionally classified as having an articulation disorder in
that they were unable to produce acceptable versions of
particular phonemes in any phonetic context. All distorted
the phones /s/ and /z/ consistently as [Ò]. This is not
surprising, since the co-occurrence of phonological and
articulation (or phonetic) disorder has already been
recognized (Fey, 1992; Kamhi, 1992). In all three phonological subgroups about half of all children showed an
interdental production of /s/ and /z/. Given that up to 40%
of children in the normative study also evidenced interdentality, this is more likely to reflect allophonic variation
than an articulation disorder. The other subgroups—delay
and deviant-consistent and inconsistent phonological
disorder—are mutually exclusive by definition.
For most children, classification into the four subgroups
was obvious, given the strict criteria. There were only a
few cases where children made errors that raised doubts.
Two children from the delayed subgroup made up to three
vowel errors. Vowel errors are atypical of normally developing children and if consistently used would indicate disorder.
Six children made errors on up to three lexical items that
were atypical of normal development. In the current study,
these children were classified as delayed because these few
errors were the only sign of phonological disorder as
opposed to delay. In a clinical situation, any ambiguity in
data from a standardized assessment procedure could be
explored in depth to ensure correct diagnosis.
Classification of subgroups of phonological disorder is
currently a controversial topic. Although the use of a
medical model (e.g., Shriberg, 1994, 1997) provides
important information concerning factors influencing
causal and maintenance factors, it has limited clinical
applicability. By the time a child is referred for assessment,
a number of causal and maintenance factors may be
apparent (e.g., history of otitis media, older sibling who
interprets for the child with a speech disorder, and family
history of speech disorder). Given that a clinician’s task is
to remediate the presenting problem, classification in terms
of the surface speech error patterns provides more relevant
information for determining treatment targets. Previous
research has indicated that specific speech error pattern
profiles are associated with differing deficits in the speech
processing chain. Consistent use of nondevelopmental
error patterns is associated with deficits in phonological
awareness (Leitão et al., 1997); inconsistency is associated
with deficits in phonological assembly (Bradford & Dodd,
1994, 1996). Further, clinical research trials suggest that
specific treatment approaches targeting different aspects of
the speech processing chain are most cost effective (e.g.,
Bradford & Dodd, 1998; Dodd & Bradford, 2000). The
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
finding that, irrespective of the language being learned, the
same predominant surface error patterns are evident in
approximately the same proportions of children with
speech disorders emphasizes the clinical importance of
using a behavioral as opposed to a medical model in the
classification of speech disorders.
Conclusion
It was hypothesized that the nature of speech development and its disorders is of universal character. Therefore,
classifications of speech disorders found in speakers of one
language can be validated by crosslinguistic research. The
results of this crosslinguistic study of 100 monolingual
German-speaking children support the existence of the four
hypothesized subgroups of speech disorders found in
English-speaking children: articulation disorder, delay, and
deviant-consistent and inconsistent phonological disorder.
Acknowledgments
We would like to thank all children, parents, and preschool
teachers for their participation and interest. A special thank you
goes to the private practices of speech-language pathologists
Karen Grosstück and Holger Schultze for making this study
possible. Thanks to Nicole Boheim for her transcription and
Sharon Crosbie and Carola Hofmann for help with classification
reliability. Further, we are grateful for the financial support given
by the Economic and Social Research Council.
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Received November 29, 2000
Accepted February 5, 2001
DOI: 10.1044/1058-0360(2001/026)
Contact author: Annette V. Fox, PhD, Kaiser-Friedrich-Ufer 24,
20253 Hamburg, Germany. E-mail: [email protected]
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
Appendix A
Appendix C
List of Test-Items
Developmental Error and Acquisition Patterns in Normally
Developing German-Speaking Children
Mond
Eimer
Baum
Ball
Gabel
Blume
Brille
Brief
Pilz
Wippe
Korb
Pferd
Apfel
Topf
Pflaster
Vogel
Marienkäfer
Schiff
Flasche
Frosch
Wurst
Löwe
Lampe
Teller
Ball
Nuß
Kanne
Telefon
Dusche
Feder
Rad
Drachen
Tasse
Auto
Bett
Traktor
[m]
[m]
[m]
[b]
[b]
[bl]
[b‰]
[b‰]
[p]
[p]
[p]
[pf]
[pf]
[pf]
[pfl]
[f]
[f]
[f]
[fl]
[f‰]
[v]
[v]
[l]
[l]
[l]
[n]
[n]
[n]
[d]
[d]
[t]
[d‰]
[t]
[t]
[t]
[t‰]
Zitrone
Jäger
Eichhörnchen
Milch
Taucher
Buch
Roller
Schere
Gießkanne
Nagel
Berg
Glas
Gras
Grün
Schlange
Anker
Kuh
Jacke
Sack
Kleid
Krokodil
Knopf
Quak
Sonne
Hase
Haus
Hexe
Zwerg
Zange
Katze
Pilz
Schuh
Tasche
Fisch
Schlüssel
Schmetterling
[t‰]
[j]
[C]
[ç]
[x]
[x]
[‰]
[‰]
[g]
[g]
[k,ç]
[gl]
[g‰]
[g‰]
[N]
[Nk]
[k]
[k]
[k]
[k]
[k‰]
[kn]
[kv]
[z]
[h], [z]
[s]
[ks]
[tsv]
[ts]
[ts]
[ts]
[S]
[S]
[S]
[Sl]
[Sm]
Schnecke
Schrank
Schwein
Spinne
Spritze
Stuhl
Kiste
Nest
Strumpf
Rutsche
Fenster
Heizung
Gespenst
Schornstein
Zebra
Bild
Punkt
Bank
Arzt
Hund
Gitarre
Tiger
Erdbeere
kaputt
Unfall
Elefant
springt
[Sn]
[S‰]
[Sv]
[Sp]
[Sp‰]
[St]
[st]
[st]
[St‰]
[tS]
[nst]
[N]
[Sp], [nst]
[nSt]
[b‰]
[lt]
[Nkt]
[Nk]
[tst]
[nt]
TABLE C1. Developmental error pattern.
Note. From Fox, A. V., & Dodd, B. Der Erwerb des phonologischen
Systems in der deutschen Sprache. Sprache-Stimme-Gehör,
Thieme, Stuttgart, Germany. Reprinted by permission.
Table C2. Acquisition patterns for phonetic and phonemic
inventory.
Appendix B
25-Word Inconsistency Test–List of Items
Träcker
Flasche
Fisch
Unfall
Knöpfe
Marienkäfer
Eichhörnchen
Strumpf
Rutsche
Gitarre
Elefant
Schwein
Springt
Schlüssel
Spritze
Krokodil
Gespenst
Brief
Drachen
Frosch
Schiff
Zwerg
kaputt
Glas
Tiger
Age
Group
Age
1
2
3
4
5
6
7
1;6–1;11
2;0–2;5
2;6–2;11
3;0–3;5
3;6–3;11
4;0–4;5
4;6–4;11
Phonetic
Inventory
mbdtn
pfvl
x g k h ‰ pf
jN
C
S
Phonemic
Inventory
mpd
bn
v f l t N x h k s/z*
j ‰ g pf
ts*
C
S
Note. General acquisition criterion: 90% of the children of an agegroup had acquired the phone or phoneme (for individual criteria,
see the Analysis section).
* /T/, /D/, and /tT/ were accepted as phonemically correct.
Fox & Dodd: Differential Diagnosis of Phonological Disorders
305
Appendix D
Error Patterns in Children With Speech Disorders
TABLE D1. Articulation-disordered subgroup.
Age
56
58
58
62
64
65
66
67
67
67
67
71
74
75
75
75
75
76
78
80
Int
Lat
✩
✩
✩
✩
✩
✩
✩
★
✩
✩
✩
★
✩
✩
✩
✩
✩
✩
✩
✩
✩
★
★
Note. Age = age presented in months; Int = interdentality; Lat = lateral production of sibilants (→ Ò); ✩ = age-appropriate process; ★ = ageinappropriate process.
TABLE D2. Delay subgroup.
Developmental Error Patterns
Age
39
40
43
44
47
47
48
50
50
52
52
53
53
53
53
55
55
55
56
56
58
58
59
59
59
62
Asm ClR
✩
✩
✩
✩
✩
✩
✩
✩
CD WSD Fro
✩
★
★
★
★
★
★
✩
★
✩
✩
✩
✩
★
★
✩
Voi BkS GlR Daf
★
✩
✩
Sto
Developmental Error Patterns
★
★
★
★
★
★
★
★
✩
★
★
✩
✩
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
✩
✩
★
Age
62
62
63
63
63
64
64
65
65
65
66
66
67
67
67
71
72
73
73
74
78
79
80
80
81
Asm ClR
CD WSD Fro
Sto
Voi BkS GlR Daf
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
Note. These data do not include articulatory patterns. Age = age presented in months; ✩ = age-appropriate process; ★ = age-inappropriate
process.
Abbreviations: Asm = assimilation; CIR = cluster reduction; CD = initial or final constant deletion; WSD = weak syllable deletion; Fro = fronting
of plosures/sibilants; Sto = stopping; Voi = voicing, devoicing, or cluster devoicing; BkS = backing of plosives; GlR = glottal replacement; Daf
= deaffrication.
306
American Journal of Speech-Language Pathology • Vol. 10 • 291–307 • August 2001
TABLE D3. Deviant-consistent subgroup.
Developmental Error Pattern
Nondevelopmental Error Pattern
Age Asm ClR CD WSD Fro Sto Voi BkS GlR Daf
41
49
49
50
51
54
53
53
54
58
60
63
65
69
70
71
91
★
✩
✩
✩
✩
✩
✩
✩
✩
★
★
★
★
★
★
★
★
★
★
★
★
★
✩
★
✩
✩
✩
✩
★
★
★
★
★
Vow Met Affr f-T
s-f CD IntC BkP UnD Gl/l/ ‰/l-j ‰-s FavS AlloClCh ND/k
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
★
Note. These data do not include articulatory patterns.
Age = age presented in months; ✩ = age-appropriate process; ★ = age-inappropriate process.
Abbreviations: Asm = assimilation; ClR = cluster reduction; CD = initial or final consonant deletion; WSD = weak syllable deletion; Fro =
fronting of plosives/sibilants; Sto = stopping; Voi = voicing, devoicing, cluster devoicing; BkS = backing sibilants; GlR = glottal replacement;
Daf = deaffrication; Voc = vocalization of /l/; Nas = nasality; Vow = vowel errors; Met = metathesis; Affr = affrication; f-T = /f/→[T]; s-f =
/s/→[f]; CD = unusual consonant deletion; intC = intrusive consonant; BkP = backing of plosives; UnD = unusual developmental processes;
Gl/l/ = glottal replacement of /l/; ‰/l-j = /‰/, /l/→[j]; ‰-s = /‰/→[s]; FavS = favourite sound; Allo = allophonic use of a sound class (i.e., nasals,
fricatives); ClCh = cluster changes or assimilation; ND/k = /N/ deletion before /k/.
Fox & Dodd: Differential Diagnosis of Phonological Disorders
307