PHONOTACTIC KNOWLEDGE OF WORD BOUNDARIES AND ITS USE IN INFANT SPEECH-PERCEPTION

The development of a lexicon critically depends on the infant's abilit y to identify wordlike units in the auditory speech input. The present study investigated at what age infants become sensitive to language-s pecific phonotactic features that signal word boundaries and to what e xtent they are able to use this knowledge to segment speech input. Exp eriment 1 showed that infants at the age of 9 months were sensitive to the phonotactic structure of word boundaries when word-like units wer e presented in isolation. Experiments 2 to 5 demonstrated that this se nsitivity was present even when critical items were presented in conte xt, although only under certain conditions. Preferences for legal over illegal word boundary clusters were found when critical items were em bedded in two identical syllables, keeping language processing require ments and attentional requirements low. Experiment 6 replicated the fi ndings of Experiment 1. Experiment 7 was a low-pass-filtered version o f Experiment 6 that left the prosody of the stimulus items intact whil e removing most of the distinctive phonotactic cues. As expected, no l istening preference for legal over illegal word boundary clusters was found in this experiment. This clearly suggests that the preferential patterns observed can be attributed to the infants' sensitivity to pho notactic constraints on word boundaries in given language and not to s uprasegmental cues.