Word frequency and prosody bootstrap basic word order in prelexical infants

Abstract

Languages systematically vary in their basic word order, which infants need to learn as they acquire their native language. Here I present evidence for the prosodic bootstrapping of word order. Specifically, two behavioral experiments and one brain imaging study word are reviewed supporting the hypothesis that word frequency and phrasal prosody serve as powerful cues to help infants bootstrap the basic lexical categories of functors and content words and guide infants about the relative order of these two categories in their native language. The acoustic realization of prosodic prominence in phonological phrases correlates with basic word order, as functor-initial languages typically rely on phrase-final lengthening, while functor-final language on phrase-initial pitch and/or intensity rise (Nespor et al. 2008). The first study shows that 8-month-old infants can use this acoustic cue to determine the word order of an artificial language. A second study shows that infants expect this prosodic information to be aligned with word frequency, i.e. frequent words to be prosodically non-prominent, as are natural language functors. A near-infrared spectroscopy imaging study suggests that sensitivity to the acoustic realization of prosodic prominence and the resulting rhythmic (iambic/trochaic) grouping derives from babies’ prenatal experience with speech.