An Ultrasound Study of Lingual Coarticulation in Children and Adults

There have been a number of studies which compared coarticulatory patterns in children and adults, but these studies have produced conflicting results, particularly with respect to anticipatory lingual coarticulation. This study used articulatory measures derived from ultrasound imaging, in order to establish any differences between child and adult coarticulatory patterns, and to quantify the degree of variability in children’s and adults’ productions. The participants were four adults and four normally developing children aged 6 to 9 years, all speakers of Standard Scottish English. The data were the syllables / i/, / u/ and / a/, in the carrier phrase “It’s a ... Pam” (ten repetitions). Synchronised ultrasound and acoustic data were recorded using the Queen Margaret University ultrasound system. Extent of consonantal coarticulation and within-speaker variation in child and adult productions were compared according to a new ultrasound-based measure of coarticulation. A significantly greater amount of anticipatory lingual coarticulation was found in children than in adults. Much within-group variability was observed, in both age groups. Within-speaker variability was significantly greater in children than in adults. These results are in agreement with some previous studies. Possible reasons are discussed for some of the contradictions in the literature on child and adult coarticulation.