A Question of Scope? Direct Comparison of Clear and In-Focus Speech Productions.

Parallels in the production of clear speech and words under prosodic focus suggest that both may be realized in the same way: as hyper-articulated speech. To directly investigate this possibility, school-aged children and college-aged adults produced target words in a default conversational style, a clear speech style, and with prosodic focus. The results were that children and adults both produced target vowels more distinctly and with greater mouth opening in the clear speech and prosodic focus conditions than in the default condition. Whereas the temporal scope of production changes varied as a function of condition in adults' speech, there was no evidence of this in children's speech.