The quantitative ultrasound study of tongue shape and movement in normal Persian speaking children

Ultrasound research on speech production in normal speakers has long used quantitative measurements in different languages. However, no studies in this area have been conducted in the Persian language. This study investigated Persian speaking children scores on two single curve measures of tongue shape, based on midsagittal tongue shape data from ultrasound imaging.

This is a cross-sectional study conducted on four 7-8 years old Persian speaking children. The data for analysis was collected using an ultrasound machine in 2018-2019. The stimuli included a range of consonants including/p/,/t/,/f/,/k/and/s/in consonant-vowel sequences, with the vowels/a/and/i/. The measures do not require head stabilization. Statistical analyses were done using Linear mixed models in lmer software package of R version 3.6.2. The results were performed by Chi-squared and Tukey post hoc tests in R.

In all of the consonants, the mean of two single curve measures in the context of/i/was greater than the context of/a/. However, there was no significant effect of the vowel context on one measure for the/k/. Also, these measures were significantly different in each of the Persian consonants and they showed consistent patterns across all of the participants (P<0.001).

It seems the single curve measures are the valid value of tongue dorsum excursion for Persian speaking children. This study showed that measures of single curves are reliable for distinguish between consonants in vowel contexts and created robust results on lingual coarticulation of the consonants without the use of head stabilization.