Acoustic correlates of stress in English adjective-noun compounds

This study investigates the phonetic implementation of stress in American English compounds by measuring the interaction of stress cues with different intonation patterns. Participants in an experiment produced compounds and phrases such as greenhouse and green house in different prosodic positions and sentence types to elicit the contrast in a variety of intonational environments. Intonation patterns were labeled and carefully controlled for, and measurements of vowel duration, intensity (dB) and pitch (in semitones) were compared. The results of the experiment reveal clear patterns that distinguish compounds from phrases, and provide acoustic evidence of the characteristic prominence pattern for adjective + noun compounds. Intensity is a significant cue for compound stress in all but the rising intonation environments, such as questions. Duration differences are a reliable cue in exactly this intonational environment, and also in certain clause-final intonation patterns, which similarly contain a high boundary tone. Distinctive pitch patterns were also found. The results suggest that interactions with the intonational and prosodic environment determine which phonetic cues will signal the stress pattern of a compound in a given utterance.