age, syntactic complexity, articulatory kinematics, speech, language


Purpose: This study investigated the effect of age on articulatory movement and stability in young, middle-aged, and older adults. It also examined the potential influence of linguistic complexity on speech motor control across utterances that differed in their length and grammatical complexity.
Method: There were 60 participants in three age groups: 20-30 years, 40-50 years, and 60-70 years, with equal numbers of men and women in each group. The speakers produced 10 repetitions of five different stimuli, each of which included the same bilabial-loaded phrase in different grammatical contexts, while their lip movements were recorded.
Results: Participants from the 60 year-old group had significantly longer utterance durations, while those from the 20 year-old group had the highest jaw spatiotemporal index (STI) values. There were significant differences in the upper lip STI, displacement, and velocity, as well as in vocal intensity for the longer, complex conditions compared to the shorter, phrase-only task. Overall, the differences in performance were minimal across grammatical complexity levels that were equal in length.
Conclusion: These findings suggest that speech motor control matures beyond young adulthood and that linguistic complexity in a repetitive task does not appear to have a consistent effect on measures of speech movement.

Original Publication Citation

Dromey, C., Boyce, K., & Channell, R.W. (2014). Effects of age and syntactic complexity on speech motor performance. Journal of Speech, Language, and Hearing Research, 57, 2142-2151.

Document Type

Peer-Reviewed Article

Publication Date


Permanent URL


American Speech-Language-Hearing Association




David O. McKay School of Education


Communication Disorders