Acoustic characteristics of tense and lax vowels across sentence position in clear speech.

This study examines how the inherent properties of tense and lax vowels interact with external factors, such as speech style (clear vs conversational) and position (sentence-medial vs sentence-final). Twelve speakers of American English recorded productions of the tense /i,u,ɑ/ and lax /ɪ,ɛ,æ,ʊ,ʌ/ vowels, all of which were lengthened and decentralized to a similar degree in clear speech. Furthermore, unlike tense vowels, lax vowels had a greater vowel space area in sentence-medial position, which was primarily driven by high vowels' decreased 1. Therefore, the defining properties of lax vowels (short duration and centralization) were altered by both speech style and sentential position.