Speech motor control timing was examined by means of a multiple correlational analysis involving interarticulatory delay and speech rate as predictor variables, and four subsyllabic time segments of the syllable [ka] as dependent variables. The hypothesis was that the two putative temporal constraints have differential predictive capacity for various segments of the syllable. Results from 11 subjects were in support of the hypothesis. Syllable onset duration was reliably predicted by the linear addition of interarticulatory delay and speech rate, while the duration of the midportion of the syllable was nearly exclusively predicted by the overall speech rate. This model was found to be applicable to all conditions of normal and clenched teeth, context-free and contextual, normally paced and rapid speech production, with minor differences in predictive capacity for different conditions.