| Parents speak to their children in sentences from the first days of infancy, yet little is known about sentence comprehension by children still at the one-word production stage. Speech prosody appears to be particularly relevant to early sentence processing: Acoustic correlates of syntactic structure are especially reliable in infant-directed speech, prompting researchers to hypothesize that prosodic information provides young learners with an initial means toward acquiring syntax. However, although it has been demonstrated that year-old infants are able to perceive acoustic cues to constituent boundaries, there has been no evidence to date that children make use of such cues in understanding speech.;The experiments reported here investigate the roles of prosody and syntax in fifteen-month-olds' comprehension of a sentence-embedded novel word. A preferential-looking task was used, in which subjects indicated their interpretation of a linguistic stimulus by matching it with one of two simultaneously-presented images that afforded contrasting referents (i.e., a novel action and a novel object). Three types of stimulus utterances were used: a single prosodic unit with internal divisions (i.e., a long sentence), two prosodic units (i.e., two consecutive sentences), and a single prosodic unit without internal divisions (i.e., a short sentence).;The results suggest that children this age will interpret a novel word as an object label when that word is part of a single prosodic unit (i.e., a single sentence, regardless of length, and regardless of its syntax or prosodic substructure). However, children can interpret a novel word as an action (i.e., can be directed away from what is generally held to be a strong interpretive bias) when (a) the utterance contains preceding object labels to which the action can refer, and (b) the known words and the novel word are within separate prosodic units (i.e., two sentences).;It is hypothesized that children at this age map semantic entities onto prosodic units characterized by clear boundaries (i.e., ending in a steep drop in fundamental frequency and followed by a long pause). Furthermore, they employ a "proto-grammar" to combine two such entities into a propositional whole. |
