Acoustic and perceptual cues for compound-phrasal contrasts in Vietnamese

This paper reports two series of experiments that examined the phonetic correlates of lexical stress in Vietnamese compounds in comparison to their phrasal constructions. In the first series of experiments, acoustic and perceptual characteristics of Vietnamese compound words and their phrasal counterparts were investigated on five likely acoustic correlates of stress or prominence (f0 range and contour, duration, intensity and spectral slope, vowel reduction), elicited under two distinct speaking conditions: a "normal speaking" condition and a "maximum contrast" condition which encouraged speakers to employ prosodic strategies for disambiguation. The results suggested that Vietnamese lacks phonetic resources for distinguishing compounds from phrases lexically and that native speakers may employ a phrase-level prosodic disambiguation strategy (juncture marking), when required to do so. However, in a second series of experiments, minimal pairs of bisyllabic coordinative compounds with reversible syllable positions were examined for acoustic evidence of asymmetrical prominence relations. Clear evidence of asymmetric prominences in coordinative compounds was found, supporting independent results obtained from an analysis of reduplicative compounds and tone sandhi in Vietnamese [Nguye;n and Ingram, 2006]. A reconciliation of these apparently conflicting findings on word stress in Vietnamese is presented and discussed.