Can a model of overlapping gestures account for scanning speech patterns?

A simple acoustic model of overlapping, sliding gestures was used to evalua te whether coproduction was reduced for neurologic speakers with scanning s peech patterns. F2 onset frequency was used as an acoustic measure of copro duction or gesture overlap. The effects of speaking rate (habitual versus f ast) and utterance position (initial versus medial) on F2 frequency and pre sumably gesture overlap, were examined. Regression analyses also were used to evaluate the extent to which across-repetition temporal variability in F 2 trajectories could be explained as variation in coproduction For consonan ts and vowels. The lower F2 onset frequencies for disordered speakers sugge sted that gesture overlap was reduced for neurologic individuals with scann ing speech. Speaking rate change did not influence F2 onset frequencies, an d presumably gesture overlap, for healthy or disordered speakers. F2 onset frequency differences for utterance-initial and -medial repetitions were in terpreted to suggest reduced coproduction For the utterance-initial positio n. The utterance-position effects on F2 onset Frequency, however, likely we re complicated by position-related differences in articulatory scaling. The results of the regression analysis indicated that gesture sliding accounts , in part, for temporal variability in F2 trajectories. Taken together, the results of this study provide support for the idea that speech production theory For healthy talkers helps to account for disordered speech productio n.