The acquisition of the voicing contrast in word-initial bilabial and alveolar stops--atypical data from Hungarian

The present study aims to investigate, through acoustic analysis, the acquisition of voicing contrast in Hungarian word-initial bilabial and alveolar stops (p/b and t/d) produced by 15 children with primary language disorders between 5;6 and 7;7 years of age. Data collection was based on a picture-naming task involving at least four different pictures for each segment tested. The elicited data were audio-recorded and then evaluated in terms of the proportion of pre-voiced stops per target category, the duration of voice onset time (VOT), and the presence of other phonetic features. The results revealed that, while all target voiceless stops are produced without pre-voicing, there is a bimodal distribution of VOTs for target voiced categories. Regarding the duration of VOTs, accurate realisations show average VOTs of immature values, and no sub-phonemic level differences were revealed in the distribution of VOTs for inaccurate realisations. Furthermore, voiceless realisations present frequently double/multiple release bursts. Findings are discussed in relation to a study on VOT distribution in the speech of typically developing children and to suggestions for further investigations.