Syllable Timing in Repetition Disfluency

This paper investigates rhythmic patterns in 3-cycle repetition disfluency (e.g. We went to the park and1 and2 and3 watched the birds...). Results show a harmonic timing effect: in a slow-speech set of corpus data, the distribution of and2 phases relative to the and1 to and3 interval is trimodal (χ = 20.1, p < .005), with modes approximating low-order harmonic ratios (1/3, 1/2, 2/3). A task-dynamic coupled-oscillators model can represent the structure of the observed distribution as attractor-structure in a potential function, accounting for why harmonic modes are observed. Furthermore, the model can treat the ratio of oscillator amplitudes as a control parameter representing speech-rate; as this parameter is varied, higher-order modes become unstable, explaining why trimodality is not observed in a fast-speech subset of the data. In contrast to previous experimental findings of harmonic timing, the effects observed here operate on a smaller time scale and cannot be attributed to an external stimulus or self-entrainment.