The Acoustic Manifestation of Prominence in Stressless Languages

Languages frequently express focus by enhancing various acoustic attributes of an utterance, but it is widely accepted that the main enhancement appears on stressed syllables. In languages without lexical stress, the question arises as to how focus is acoustically manifested. We thus examine the acoustic properties associated with prominence in three stressless languages, Indonesian, Korean and Vietnamese, comparing real three-syllable words in non-focused and focused contexts. Despite other prosodic differences, our findings confirm that none of the languages exhibits stress in the absence of focus, and under focus, no syllable shows consistent enhancement that could be indirectly interpreted as a manifestation of focus. Instead, a combination of boundary phenomena consistent with the right edge of a major prosodic constituent (Intonational Phrase) appears in each language: increased duration on the final syllable and in Indonesian and Korean, a decrease in F0. Since these properties are also found in languages with stress, we suggest that boundary phenomena signaling a major prosodic constituent break are used universally to indicate focus, regardless of a language’s word-prosody; stress languages may use the same boundary properties, but these are most likely to be combined with enhancement of the stressed syllable of a word.