Evidence of segmental articulations: Acceleration determines vowel segment duration in Swedish Word Accents

Abstract

This study addresses a one-to-one relation between articulation and acoustics at segment boundaries. The study focuses on Swedish word accents and how a rising or falling tone affect vowel segment duration. The paper explains how segment boundaries are a result of rapid movements of the articulators. In the acceleration profile, this is identified as peak acceleration, which can be measured. The timing of two acceleration peaks (the distance between them is referred to as a posture interval ) determines the duration of the acoustic segment. The purpose of the study is to see whether the posture intervals of active articulators correlate with the acoustic vowel segment, even if duration is affected by tonal context. To this end, acoustic and articulatory data on long and short open vowels, produced by 18 Swedish speakers, have been collected. The data includes vowel acoustic segment duration, and peak acceleration of lip and tongue tip movements. The results suggest that: a) acoustic vowel segments can be determined by timing of consonantal articulation; b) peak acceleration successfully capture the acoustic changes constituting the segment boundary, at least for nasal stops; c) laryngeal production affects all orofacial movements, as the tone affects the timing of the consonantal articulation.