From Sound to Syntax: The Prosodic Bootstrapping of Clauses

Abstract

It has long been argued that prosodic cues may facilitate syntax acquisition (e.g., Morgan, 1986). Previous studies have shown that infants are sensitive to violations of typical correlations between clause-final prosodic cues (Hirsh-Pasek et al., 1987) and that prosody facilitates memory for strings of words (Soderstrom et al., 2005). This dissertation broaches the question of whether children can use this information in syntax acquisition by asking if learners can use the prosodic correlates of clauses to locate syntactic constituents. One property of certain syntactic constituents in natural languages is that they can move, so learning of constituency was inferred if participants treated prosodically-grouped words as cohesive, moveable chunks. In Experiment 1, 19-month-olds were familiarized with sentences from an artificial grammar with either 1-clause or 2-clause prosody. The infants from the 2-clause group later recognized the prosodically-marked clauses when they had moved to a new position in the sentence and had a new acoustic contour. Adults in Experiment 2 showed similar learning, although their judgments also rely on recognition of perceptually-salient words at prosodic boundaries. Subsequent experiments explored the mechanisms underlying this prosodic bootstrapping by testing Japanese-acquiring infants on English-based stimuli (Experiment 3) and English-acquiring infants on Japanese-based stimuli (Experiment 4). Infants were able to locate constituent-like groups of words with both native and non-native prosody, suggesting that the acoustic correlates of prosody are sufficiently robust across languages that they can be used in early syntax acquisition without extensive exposure to language-specific prosodic features. On the other hand, adults (Experiment 5) are less flexible, and are only able to use prosody consistent with their native language, suggesting an age- or experience-related tuning of the prosodic perceptual mechanism. This dissertation supports prosody as an important cue that allows infants and young children to break into syntax even before they understand many words, and helps explain the rapid rate of syntax acquisition.