High Durational Variability of Consonant Geminates and Their Surrounding Vowels in Stuttering Japanese Speakers' Fluent Speech

This study compared the oral reading performances of stuttering and nonstuttering Japanese speakers with respect to (a) durations of V1, V2, and Q (geminate consonant) in the (C) V1QCV2 sequence in words, (b) V1/V2, Q/3S, Q/V1, and Q/V2 durational ratios, and (c) variability coefficients for V1, V2, and Q durations, and for V1/V2, Q/3S, Q/V1, and Q/V2 durational ratios. Results showed that the means of the duration of V2 and Q, and those of the variability coefficient for V1/V2, Q/3S, Q/V1, and Q/V2 durational ratios were significantly greater for the stuttering group than for the nonstuttering group. These findings are interpreted as reflecting covert markers of stuttering events (e.g., blocking) caused through asynchronous interactions between V1, Q, and V2 in the stuttering individuals' aberrant timing system.