Acoustic and articulatory parameters during the production of the contrast between alveolar and velar stops: typical and phonological disorder data

ABSTRACT

Introduction

Speech instrumental analysis, such as acoustic and articulatory (e.g. ultrasound tongue images) may identify speakers’ undetected linguistic skills through auditory perceptual analysis.

Purpose

To compare the acoustic and articulatory parameters between alveolar and velar stops and between children with typical speech development and children with phonological disorders.

Methods

The sample consisted of fifteen children with typical speech development and seven children with phonological disorders. The corpus was organized through the target-words: /’kapə/, /‘tapə/, /‘galo/ and /‘daɾə/, into carrier phrase and spontaneously named. Simultaneous audio and video (tongue ultrasound images) recording were performed. The data was analyzed in acoustic and articulatory ways.

Results

Six (spectral peak, centroid, variance, skewness, kurtosis and consonant-vowel transition) of the nine acoustic parameters investigated did not demonstrate any distinctions between children with and without speech alterations. Only spectral peak and consonant-vowel transition values were not significant for differentiating the target contrast. In relation to the ultrasound data, the proportion of significant axes of the tongue’s anterior and posterior region showed some significant variations in the typical group, different from the group with phonological disorders. The tongue curves also evidenced particularities between the groups.

Conclusion

The acoustic and articulatory parameters provided evidence about the phonic contrast between alveolar and velar stops in the studied sample. It was observed an articulatory refining of children with typical speech development and the presence of covert contrast in the speech of children with phonological disorders.

Speech; Ultrasonography; Speech acoustics; Child; Speech sound disorder