An ultrasound study of the development of lingual coarticulation during childhood

Abstract

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 six age groups of Scottish English speaking children between three and thirteen years old. Methods. Vowel-on-consonant anticipatory coarticulation was analysed using ultrasound imaging data on tongue shape from four 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.