Phonology

2.3.3.1 A merged format

The basis of the development of this part of the test was evidently the DAPPLE study, followed by a combination of two further tests: PDSS (Phonology subtest) and the screening PLAKSS II.

Therefore, it is deemed necessary to first describe a few of the characteristics of each procedure separately, before analysing the “adapted” and combined format that we used.

2.3.3.2 The original phonology task (DAPPLE study)

The original task was based on diagnostic screening that is part of the Diagnostic Evaluation of Articulation and Phonology (DEAP; Dodd, Zhu, Crosbie, Holm, & Ozanne, 2002). Although the detailed procedure of the screening is described later, it might be said that its overall function is to identify which “aspects of the speech system need further investigation” (DEAP; Dodd, Zhu, Crosbie, Holm, & Ozanne, 2002, p.3). This is achieved through the repeated naming of 10 pictures with a

74 speech sound stimulability task in-between. These ten original test items have been chosen to cover almost all consonants, some clusters, and several vowels. The main idea of this screen is that if a child is not able to successfully imitate speech sounds that 90% of children of the same age group are able to, then further detailed tests of Articulation and Oro-motor functioning are to be administered. In the case of successful imitation of isolated sounds that are erroneously produced during the picture naming trial, the clinician should administer the (detailed) Phonology Assessment (Dodd, Zhu, Crosbie, Holm, & Ozanne, 2002). During this process, it is important to investigate the type of error patterns, i.e., whether they are typical or atypical, as the latter would be prioritised for therapy.

Furthermore, an inconsistency rate might be derived by comparing the words that were produced differently over the two trials. An inconsistency rating of over 40% also warrants further investigation through the Articulation Assessment of the DEAP, as such a performance might be an indication of verbal Dyspraxia or other articulation difficulties.

For information, the psychometric characteristics of original DEAP assessment (whole battery) are very good (Concurrent validity: r = .95, Mean inter-rater reliability 90%).

2.3.3.3 Adaptation in German

During our attempt to adapt said screening to German, we could not overlook the fact that DEAP in its entirety has already been adapted by Annete Fox-Boyer (2014) under the name PLAKSS

(Psycholinguistische Analyse kindlicher Aussprachestörungen). Since this is an already validated, standardised screening, including the selection of specific words, its selection was evident. As mentioned in the manual of PLAKSS-II (Fox-Boyer, 2014, p.7), the specific instrument is not just a translation of the original but rather an informed adaptation in German, which allows to gauge if a child’s phonological development follows the typical developmental patterns or not, if therapy is warranted, and proposes intervention plans. Its standardisation was based on a very large study including some 650 children (Fox-Boyer, 2014).

Also, one of the advantages of this test is that it already included an additional level of adaptation, which comprises changes based on the syllabic structure/ phonological and vocabulary differences of Swiss-German. This variation was included into the list of word included in our study (Table 7).

Nonetheless, the actual screening that is included in the PLAKSS II presented with one important difference, i.e., the much higher number of items (30) compared to that of the original DAPPLE (10).

It was decided, therefore, to try and align the format of our study with that of DAPPLE and, thus, we reduced it again to 10 items. The other reason for doing this, was to make the whole process less time-consuming and demanding for the (very) young participants. During the selection process of certain

75 items, we decided to also consider the PDSS-Phonology subtest materials, as this had been our

original test. A brief description follows next.

PDSS- Phonology subtest: This subtest entails two parts, one directly looking at the realisation of speech sounds and one targeting phonological differentiation. Unfortunately, the former subtest, that is directly relevant to our study, is not a quantitative instrument. Although children are tested in a variety of carefully selected words, it is only possible to analyse any results qualitatively, i.e., in terms of the observed patterns of phonological substitutions. Therefore, we could not use this subtest in its original form but rather only use some of its stimuli, i.e., words that coincided with the ones chosen at the PLAKSS-II screening.

2.3.3.4 Adapted version- Phonological static test

Our instrument included a combination of stimuli taken from the previously described phonological tests: the PDSS-Phonology (Kauschke & Siegmüller, 2002) and the screening PLAKSS (Fox-Boyer, 2014). Both evaluate the production of single phonemes at word level. However, following the DAPPLE paradigm, and for methodological reasons, it was decided to select 10 pictures of words, which also appear in the PLAKSS screening, as these have been specifically selected and standardised with German-speaking children.

2.3.3.5 Characteristics of the selected phonological items

All 30 words from the PLAKSS Screening (Fox-Boyer, 2014) were developed with the idea to help cover all possible phones and phonemes of German in varying complexity and within different syllabic structure, ranging from mono- to polysyllabic words. Based on this principle, and taking into consideration the DAPPLE/DEAP paradigm, we chose 10 words that presented the maximum possible variation of phonetic complexity. In other words, we aimed to include both easy, as well as some hard items so as to identify which sounds have been mastered but also capture any difficulties and leave room for testing children’s stimulability. For instance, we incorporated some relatively easy words to detect mastery of relatively early acquired sounds, such as “Hase” and “Buch”, whereas other tested the acquisition of more complex sounds, such as r-clusters or the “sch” (/ʃ/) sounds. The list of the actual words is presented on Table 6.

For reference, as this information is necessary to interpret any of the results (see Qualitative analysis), it is important to briefly mention the typical age of acquisition of German phonemes. German

comprises 22 consonants /p b t d k g f v s z ʃ x ç h m n ŋ l R j pf ts / and 13 vowels (Fox & Dodd,

76 2001). The reported age of acquisition is presented in the table below based on the work of Melzer, Ring, Petermnann, & Rissling (2018).

Table 6. Age of acquisition of German phonemes (Melzer, Ring, Petermnann, & Rissling, 2018)

Age Phonemes

1;6-1;11 b m p

2;0-2;5 b n

2;6-2;11 v f l t ŋ x h k s z

3;0-3;5 j R g pf

3;6-3;11 ts

4;0-4;5 ç

4;6- 4;11 ʃ

The version of the words IPA- Pronunciation was based on the PLAKSS Screening Schweiz. It is important to note that for a few sounds, however, such as /k/ or /r/, correct realisations of the specific sounds, both in High German as well as in Swiss German, were considered as successful responses.

More specifically, where /r/ is concerned both the apical /r/([ɾ]) as well as the uvular /r/ ([ʁ]) were considered correct. In the case of /k/ both /k/ as well as /kx/ were considered successful.

The following table includes both the High- and Swiss-German version of the selected words.

Table 7. List of words of the Phonological task

Word in High-German IPA (or Swiss-German

version)

1.Hase hɑːzə (hɑːs)

2.Jacke jakə

3.Knöpfe knœp͡fə (xnøp͜f)

4.Buch bux (buex)

5.Schiff ʃɪf

6.Schlüssel ʃlʏsəl

7.Katze kat͜ sə (xat͜s)

8.Frosch fʀɔʃ

9. Drache dʀɑxə

10.Schmetterling ʃmɛtɐlɪŋ

77 2.3.3.6 Phonology procedure (static-dynamic)

Children’s ability to correctly produce previously misarticulated sounds (stimulability) was evaluated using the same materials, i.e., the same 10 words used in the static test. The procedure is entirely based on the methodology of the phonology section of the DAPPLE and thus, slightly differs from the PLAKSS procedure (see below).

The whole process was divided in the following parts: a) picture naming (static), b) stimulability testing (dynamic), and c) repetition of picture naming (dynamic).

a) Picture naming (static): Children were shown ten cards that depicted the previously presented words. The examiner said: “What is this?” Their response was transcribed into the

corresponding column on the form. If the child did not respond or provided a wrong response, a first cue was provided to elicit the target word, following the PLAKSS paradigm, in the form of a “close phrase” (completion of a phrase with a word, such as “There hops a little...

(rabbit)”. If this cue was not successful a second cue was provided in the form of a forced alternative, for example “is this a rabbit or a jacket?”. If this did not work either, children were asked to repeat the target word; in that case their response was marked with an “R” next to it.

b) Stimulability of sounds (dynamic): All the sounds that children failed to produce correctly during picture naming were highlighted on the corresponding IPA column of the scoring form.

This phase tested to what extent these non-correctly produced sounds might be elicited following a model. Children were asked to “repeat what was said to them” (by the examiner).

The tested sounds were to be repeated twice as single sounds and twice within syllables. In cases of blends, such as “fr”, each of the sounds was tested separately. If the children failed to repeat correctly or did not repeat any of the proposed sounds, these were to be noted

(transcribed) separately into the corresponding column of the scoring form.

c) Repetition of picture naming (dynamic): The picture naming process was repeated, and children’s productions were transcribed in the corresponding column and compared to the one of the initial phases.

Scoring: all the sounds that were differently produced during the two picture naming phases were summed up (a) and added to the sum of all produced words (b). This sum was then used to calculate the Inconsistency ratio of each child using the formula (a + b) * 100.

78 As per the DEAP/DAPPLE as well as (the PLAKSS methodology), an Inconsistency rate of over 40%

would warrant further investigation through a more detailed Articulation test, as this would be indicative of highly inconsistent sound productions, which often are an indication of verbal dyspraxia (Crary, 1993). On the other hand, a low Stimulability score, would probably warrant a more detailed phonological assessment. In all cases, it is important to evaluate the type of error patterns as more atypical errors would be a priority for therapy. Finally, it is important to note that because of the way that the Inconsistency rating (ratio) was calculated, taking into consideration the sound production of both trials, before and after modelling, it is also considered as a Dynamic score.