An Ultrasound Study of the Development of Lingual Coarticulation during Childhood

Background/Aims: There is growing evidence that coarticulation development is protracted and segment-specific, and yet very little information is available on the changes in the extent of coarticulation across different phonemes throughout childhood. This study describes lingual coarticulatory patterns in 6 age groups of Scottish English-speaking children between 3 and 13 years old. Methods: Vowelon-consonant anticipatory coarticulation was analysed using ultrasound imaging data on tongue shape from 4 consonants that differ in the degree of constraint, i.e., the extent of articulatory demand, on the tongue. Results: Consonant-specific age-related patterns are reported, with consonants that have more demands on the tongue reaching adolescent-like levels of coarticulation in older age groups. Within-speaker variability in tongue shape decreases with increasing age. Conclusion: Reduced coarticulation in the youngest age group may be due to insufficient tongue differentiation. Immature patterns for lingual consonants in 5- to 11-year-olds are explained by the goal of producing the consonant target overriding the goal of coarticulating the consonant with the following vowel.