FEATURE ANALYSIS OF SINGLETON CONSONANT ERRORS IN DEVELOPMENTAL VERBAL DYSPRAXIA (DVD)

The aim of this study is to quantify diagnostic characteristics relate d to consonant production of developmental verbal dyspraxia (DVD). For this, a paradigmatic and syntagmatic feature-value analysis of the co nsonant substitution and omission errors in DVD speech was conducted. Following a three-step procedure, eleven clear cases were selected fro m a group of 24 children with DVD. The consonants produced in a word a nd nonsense-word imitation task were phonetically transcribed and tran sferred to confusion matrices, which allows for a feature and feature- value analysis. The analysis revealed that children with DVD (a) show low percentages of retention for place and manner of articulation and voicing, due to high substitution and omission rates; (b) show a parti cularly low percentage of retention of place of articulation in words, which, together with error rate, is strongly related to severity of i nvolvement; (c) are inconsistent in their feature realization and feat ure preference; and (d) show a high syntagmatic error rate. These resu lts form a quantification of diagnostic characteristics. Unexpectedly, however, very few qualitative differences in error pattern were found between children with DVD and a group of 11 age-matched children with normal speech. Thus, although the children with DVD produced higher s ubstitution and omission rates than children with normal speech, the s peech profiles of both subject groups are similar. This result stresse s the importance of interpreting profiles, not isolated symptoms. The hypothesis to consider DVD as a deficit in the phonological encoding p rocess is discussed.