Lingual Coarticulation in Preadolescents and Adults: An Ultrasound Study. ESRC End of Award Report, RES-000-22-4075

Abstract

When people combine sounds to make words, there is overlap in the tongue movements involved in articulating individual sounds, referred to as lingual coarticulation. For example, in adult speech, tongue positions at mid-consonant, in the words she- and shah-, differ because of the influence of the following vowel. The research team's earlier work showed that young children differed from adults in the extent of vowel-on-consonant coarticulation. In this project, for the first time, a quantitative analysis of the dynamics of tongue movements was performed. The project used high-speed ultrasound to measure lingual coarticulation in the syllables she-, shah-, sea- and 'Sah', comparing preadolescent children and adults, fifteen speakers in each age group. In both age groups and both consonants, the tongue position at mid-consonant was affected by the identity of the following vowel. There was no significant effect of age on the size of the vowel-related difference in tongue posture, nor on within-speaker variability in tongue placement. Age-related differences were observed in the onset of coarticulation. While in the adults, the vowel effect was present throughout the consonant for both consonants, in preadolescents the effect was apparent later into the first half of the consonant. The results of the study suggest a near-adult-like achievement in the development of lingual control by preadolescents, with respect to the coarticulation of fricative-vowel sequences. However age-related differences in timing may indicate that preadolescents have still to gain the extent of forward planning in speech production which is possible for a typical adult.