FORMANT FREQUENCY FLUCTUATION IN STUTTERING AND NONSTUTTERING ADULTS

Inferences were made regarding the vocal tract stability of stutterers ' and nonstutterers' fluent speech through the examination of formant frequency fluctuation (FFF). Fifteen adult males served as subjects co mprising separate groups of untreated stutterers, stutterers enrolled in a fluency-shaping treatment program, and nonstuttering controls. Th e steady-state portion of formant 2 (F2) was examined in the productio n of various CVC tokens and evaluated by examining the absolute Hz dif ference in F2 across consecutive glottal periods. Results of the acous tic analysis indicated a trend in FFF across the three groups. The unt reated stutterers displayed the greatest FFF, followed by the control group, with the treated stutterers displaying the most F2 stability. D iscussion focuses on the vocal tract stability displayed by each group , as well as the influence of a fluency-shaping treatment program to a chieve perceptually fluent speech. (C) 1998 Elsevier Science Inc.