Results of phonetic experiments on the acoustic correlates of lexical stress (word-level prominence) and phrasal stress (phrase-level prominence = accent) as two separate concepts in two typologically different languages, Southern British English (SBE) and Tunisian Arabic (TA), are reported in this study. Because of the confusion in the literature between the terms stress and accent, their acoustic correlates were muddled, too. To avoid this confusion, the data in this study are elicited using an experimental paradigm which allows careful investigation of the correlates of each concept independently. The duration, spectral balance, and vowel quality cues are measured. Results show cross-linguistic similarities and differences between the two languages. Unlike most world languages, duration in TA is not a correlate of stress. It is rather a correlate of accent. In the absence of focus on the target words in TA, the only phonetic characteristics of lexical stress that come in the foreground are spectral balance and F1 lowering. However, when the word is focused, Tunisian speakers rely mainly on duration and spectral balance to signal accent. SBE signals stress through three acoustic correlates which are duration, spectral balance, and vowel quality. More similarity is found for accent detection between speakers of the two languages.
The Perception of Lexical Stress in German: Effects of Segmental Duration and Vowel Quality in Different Prosodic Patterns