The influence of varying vowel phonation and duration on rhythmic grouping biases among Spanish and English speakers

Abstract

Native Mexican Spanish and American English speakers were presented with streams of alternating syllables in which vowel duration and/or creaky phonation were rhythmically varied. Participants’ grouping biases were measured as a function of their behaviour in segmenting sequences into recurrent bisyllabic units. Results indicated a creak-last grouping bias in both language groups. Duration varied singly was associated with a weak long-first grouping bias for Spanish and no consistent trend for English. When long creaky and short modal syllables were alternated, there was a significant creak-last bias and again no effect of duration in the English group. However, in the Spanish group, the long-first trend observed for duration varied singly was reversed and the effects of duration and creak were additive. Finally, when short creaky and long modal syllables were alternated, duration effects were highly significant in both language groups (fewer creak-last, more long-last groupings). Creak has been associated with final positions in higher-order prosodic domains in English, and less prevalently in Spanish. The current results show that both English and Spanish speakers can use this cue to segment rhythmic sequences into smaller, foot or word-sized units. This study is the first to establish that creak is perceptually salient for Spanish speakers and to demonstrate that the percept associated with duration can differ depending on whether it is varied singly or together with creak. More generally, the current findings show that grouping effects extend beyond intensity, pitch and duration, the features most often manipulated in rhythmic grouping studies inspired by the Iambic-Trochaic Law.