An acoustic study of lexical stress contrastivity in children with and without autism spectrum disorders.

In this exploratory study, we examined stress contrastivity within real word productions elicited via picture naming in 20 children with autism spectrum disorders (ASD) and 20 typical peers group-wise matched on age and vocabulary. Targets had a dominant pattern of lexical stress beginning with a strong-weak pattern (SW: 'caterpillar', 'butterfly') or a non-dominant pattern of lexical stress beginning with a weak-strong pattern (WS: 'tomato', 'potato'). Children produced each target twice (n = 320 productions). Acoustic measures were made for the duration, fundamental frequency, and intensity of the first two vowels for each word production. For vowel duration and fundamental frequency, children with ASD and typical peers produced a similar magnitude of stress contrastivity for SW and WS words. However, there was a significant group difference in the way contrastivity in intensity was realised for WS words whereby children with ASD produced less stress contrastivity than typical peers. Bayesian analyses were in line with our interpretation of our frequentist analyses.