Acoustic analysis of young stutterers' fluency: Preliminary observations

Abstract

The purpose of this study was to provide a preliminary description and comparison of the temporal parameters of speech production of young stutterers and normally fluent peers as represented within the acoustic waveform (for example, frication and aspiration durations) for word-initial /p/ and /b/. Subjects were 11 young stutterers (mean age = 4 yr, 5 mo) and a like number of sex- and age-matched (plus or minus 4 mo) normally fluent youngsters (mean age = 4 yr, 8 mo). Measured acoustic variables consisted of vowel-consonant transition duration (msec) and rate (Hz/msec), stop-gap, frication, and aspiration durations, voice onset time (VOT), consonant-vowel transition duration and rate, and vowel duration. Results indicated no significant differences between young stutterers and their normally fluent peers for any of the temporal measures for either /b/ or /p/, although differences in frication duration approached but did not reach significance. Correlational analyses did indicate differences between the two talker groups in that the normally fluent youngsters exhibited an inverse relation between stop-gap and aspiration durations while the young stutterers demonstrated a lack of any clear relation between these two temporal variables. Findings seem to suggest that young stutterers exhibit some difficulties effecting the relatively smooth, coordinated “compensatory” relations between laryngeal and supralaryngeal behaviors which would allow the system to remain within the “time limits” necessary for optimally smooth, ongoing, fluent speech production.