Hierarchical timing in varieties of Kuwaiti Arabic

Abstract

We examine the differences in speech timing between Hadari and Bedouin Kuwaiti Arabic dialects using the speech cycling task. In this task, wherein speakers repeat phrases in time with metronome beats, stressed vowel onsets tend to lie at harmonic phases within the Phrase Repetition Cycle (PRC), e.g., 1/2, reflecting coordination between prosodic units. Hadari has stronger stress contrast, with greater unstressed syllable reduction than Bedouin, which may afford closer alignment to harmonic phases. Six trochaic and six iambic sentences were read aloud by 22 Hadari and 23 Bedouin speakers at three metronome trial rates: slow, medium, and fast. The phases of the final (external) and medial (internal) stressed syllables – heavy, CVV(C), or light, CVC – relative to the PRC were analysed. In external and internal phases, both dialects tended to align heavy syllables closer to 1/2 phase than light syllables; however, Hadari aligned light syllables earlier in the PRC than Bedouin, which syllable duration analysis suggested may be due to greater shortening of preceding unstressed syllables in Hadari. According to spectral balance measures, Hadari contrasted three degrees of positional prominence: initial vs medial vs final, while Bedouin contrasted phrase-initial vs non-phraseinitial, suggesting different metrical structures of stress beats between dialects. We investigated the timing interaction between syllables and feet in the speech cycling data. We analysed the amplitude envelope modulation rates at foot (2-4 Hz) and syllable (4.5-12 Hz) levels, and found no effect of stress feet on the timing of syllables. The amplitude envelope’s power spectrum showed higher peaks for stressed syllables than stress feet, with higher power ratio between stress and syllable levels in Hadari than in Bedouin, which we interpreted as higher temporal stress contrast in Hadari. This work suggests that temporal coordination is an affordance of temporal acoustic cues to the interaction between rhythmic time scales.