Relating Intonational Pragmatics to the Pitch Realizations of Highly Frequent Words in English Speech to Infants

Infant-directed speech (IDS) is characterized by exaggerated intonation patterns and short, simple phrases. Because these exaggerated intonation patterns frequently convey a small, stereotyped range of emotional signals, we might expect particular words, like good or no, to be realized with consistent pitch contours. This consistency in a word’s pitch realization might facilitate word recognition, but in an intonation language like English, it could falsely suggest lexical tones, i.e., pitch variation signaling lexical contrast. The present work examines the speech input to the Englishlearning child to identify the amount, nature, and sources of pitch variation across about 3,300 tokens of 8 highly frequent words. We find two basic results. First, although intonation in IDS is prototypically exaggerated, about half the instances of frequently occurring, utterance-final words were flat in contour. Second, although each frequent word varied substantially in its intonation contours (e.g., rises versus risefalls), there were large differences among words that seem to reflect the pragmatic categories typical of each word’s use. For instance, no was generally flat or falling, and consistently low in pitch, reflecting its occurrence in prohibitive utterances; while good occurred more often with a rise-fall contour, reflecting its approbational meaning. Even the word good, however, still had more flat contours than rise-fall contours. This within-word variability in pitch realization could help the child rule out lexical tone as contrastive in English.