Acoustic Cues to Grammatical Structure in Infant-Directed Speech: Cross-Linguistic Evidence

Abstract

Several theorists have suggested that infants use prosodic cues such as pauses, final lengthening, and pitch changes to identify linguistic units in speech. One potential difficulty with this proposal, however, is that the acoustic shape of an utterance is affected by many factors other than its syntax, including its phonetic, lexical, and discourse structure. This has raised questions about how the infant could use timing and pitch as cues to any aspect of linguistic structure without simultaneously factoring out other effects. Acoustic analyses of connected samples of spontaneous speech addressed to 13.5-14-month-old infants by American English- and by Japanese-speaking mothers revealed that both utterance- and phrase-level acoustic regularities were large enough to be detected in spontaneous speech without correcting for other influences on the same acoustic features. (1) Utterance-final vowels were lengthened and underwent exaggerated pitch changes in both languages, and (2) local acoustic changes in duration (English) or pitch (Japanese) were reliably associated with some phrase boundaries within utterances. These findings suggest that a naive listener could estimate a rough prosodic template for each language based on robust acoustic patterns in observed sentences. We discuss ways in which the learner could combine acoustic and distributional analyses across utterances to acquire language-specific variations in prosodic bracketing cues and to obtain indirect perceptual evidence for the internal structure of utterances.

Prosodic disambiguation of noun/verb homophones in child-directed speech

“…In speech to children, vowels and pauses both tend to be elongated (Bernstein Ratner, 1984, 1986; Fernald, Taeschner, Dunn, Papousek, de Boysson-Bardies & Fukui, 1989; Fisher & Tokura, 1996). Child-directed speech also contains exaggerated pitch contours relative to adult-directed speech (Ferguson, 1964; Fernald, 1989), and the vowel formant space in speech to children tends to be exaggerated as well (Bernstein Ratner, 1984; Cristia & Seidl, 2014; Kuhl et al ., 1997).…”

Input Subject Diversity Enhances Early Grammatical Growth: Evidence from a Parent-Implemented Intervention

“…Natural languages expose children to multiple, correlated cues for identifying phrase structure. For example, prosodic cues such as syllable lengthening, pausing, and pitch changes at phrasal boundaries help children identify phrases (Fisher & Tokura, 1996). Natural languages also contain single word pro-forms that can be substituted for a group of words or can express similar meanings with alternative ordering of constituents; these cues to phrase structure exist across sentences in discourse (Morgan, Meier, & Newport, 1989).…”

Word Learning in Infant- and Adult-Directed Speech

“…Compared with ADS, newly mentioned words in IDS tend to be pronounced on frequency peaks (e.g., Fernald & Mazzie, 1991), undergo wider pitch changes (e.g., Fisher & Tokura, 1996), appear in utterance-final position (Fernald & Mazzie, 1991; Fisher & Tokura, 1996), and are accompanied by exaggerated syllable lengthening (e.g., Church, Bernhardt, Pichora-Fuller, & Shi, 2005; Koponen & Lacerde, 2003). Some of these features may facilitate speech processing (Soderstrom, 2007).…”