The development of motor synergies in children: Ultrasound and acoustic measurements

Abstract

The present study focuses on differences in lingual coarticulation between French children and adults. The specific question pursued is whether 4-5 year old children have already acquired a synergy observed in adults in which the tongue back helps the tip in the formation of alveolar consonants. Locus equations, estimated from acoustic and ultrasound imaging data were used to compare coarticulation degree between adults and children and further investigate differences in motor synergy between the front and back parts of the tongue. Results show similar slope and intercept patterns for adults and children in both the acoustic and articulatory domains, with an effect of place of articulation in both groups between alveolar and non-alveolar consonants. These results suggest that 4-5 year old children (1) have learned the motor synergy investigated and (2) have developed a pattern of coarticulatory resistance depending on a consonant place of articulation. Also, results show that acoustic locus equations can be used to gauge the presence of motor synergies in children.

An Ultrasound Study of the Development of Lingual Coarticulation during Childhood

“…These results suggest that constraints on the tongue related to the consonant production affect lingual coarticulation already in young children. The results from Scottish English-speaking children in this study Lingual Coarticulation during Childhood agree with previous findings on coarticulation in children speaking American English (Sussman et al, 1992;Goodell and Studdert-Kennedy, 1993;Sussman et al, 1999), Canadian French (Noiray et al, 2013), and German (Rubertus et al, 2015), showing that this aspect of the development of coarticulation is present across languages, as well as across varieties of the same language. The nature of age-related differences in coarticulation across the 3 lingual consonants provided support for hypothesis 2.…”

“…For 22-month-olds and 32-month-olds, an acoustic study of vowel-on-consonant coarticulation including the consonants /b/, /d/, and /g/, and the vowels /a/ and /i/, reported differences across stop consonant places of articulation, with evidence of reduced vowel effects on the alveolar stop (Goodell and Studdert-Kennedy, 1993). Adult-like segment-specific coarticulatory patterns for stop consonants have been demonstrated across languages for children aged 3-4 years old, in a number of studies (e.g., Sussman et al, 1992;Noiray et al, 2013;Rubertus et al, 2015). These studies used locus equations, which assess the extent of tongue advancement at the end of the consonant, specifically at the time point where any aspiration ends, i.e., the following vowel's voicing onset, and compare it to the extent of tongue advancement at the middle of the following vowel (Rubertus et al, 2015, included midconsonant as well as the consonant offset, with the same results).…”

“…The stimuli consisted of real words /pi/ ("pea"), /ti/ ("tea"), /si/ ("sea"), /ʃi/ ("she"), and /ʃa/ ("shah"), as well as the following nonsense words, which were presented to the participants as names of imaginary creatures: /pa/ ("Pa"), /ta/ ("Tah"), /sa/ ("Sah") 1 . The phonological structure of the target CV syllables was selected to provide minimal pairs for analysing vowel-on-consonant coarticulation for each of the 4 consonants, and to make it easier to compare the results with those from previous studies (e.g., Sussman et al, 1992;Nittrouer et al, 1996;Zharkova et al, 2012;Noiray et al, 2013;Reidy, 2015). The 2 vowels were chosen to provide sufficiently contrasting lingual articulations, while avoiding a confounding factor of lip rounding.…”

The coarticulation/invariance scale: Mutual information as a measure of coarticulation resistance, motor synergy, and articulatory invariance

“…We believe, however, that it is possible to use other forms of quantification of articulatory data for this purpose. Noiray et al (2013) used the LE method to quantify coarticulation of the back of the tongue from ultrasound data, by using the horizontal component of the highest point of the tongue in the ultrasound edge. MI could have also been used in that study and could be based on different types of quantification of whole-tongue images from MRI or ultrasound.…”

Using ultrasound tongue imaging to identify covert contrasts in children’s speech

“…Abakarova et al, 2015;Magloughlin, 2016;Rubertus et al, 2015;Song et al, 2013;Yip et al, 2015), as well as using quantification methods that could be employed to identify covert contrasts (e.g. Klein et al 2013;Ménard & Noiray, 2011;Noiray et al, 2013;Zharkova et al, 2015a, b).…”