Voice onset time and formant onset frequencies in Arabic stuttered speech

Neuromuscular models of stuttering consider that making transitions between phones results in inappropriate temporal arrangements of articulators in people who stutter (PWS). Using this framework, the current study examined the acoustic productions of two fine-grained phonetic features: voice onset time (VOT) and second formant (F2). The hypotheses were that PWS should differ from fluent persons (FP) in VOT duration and F2 onset frequency as a result of the transition deficit for environments with complex phonetic features such as Arabic emphatics. Ten adolescent PWS and 10 adolescent FPs participated in the study. They read and memorized four monosyllabic plain-emphatic words silently. Data were analyzed by Repeated Measures ANOVAs. The positive and negative VOT durations of/t/vs./tˁ/and/d/vs./dˁ/and F2 onset frequency were measured acoustically. Results showed that stuttering was significantly affected by emphatic consonants. PWS had atypical VOT durations and F2 values. Findings are consistent with the atypicality of VOT and F2 reported for English-speaking PWS. This atypicality is realized differently in Arabic depending on the articulatory complexity and cognitive load of the sound.