Abstract:

The phonetic coding of speech reflects both a stimulus driven process and influences from the mental lexicon. There are at least three distinct forms of influence of the mental lexicon on phonetic processing: lexical status (is the item a word), lexical neighborhood (how many words is the item similar to), and phoneme frequency (how often does the phoneme occur in the language). Using natural speech series, the identification of an ambiguous phoneme is influenced by both the lexical neighborhood of the stimulus (syllable), and the probability of occurrence of the target phonemes in the language. Listeners consistently identify ambiguous phonemes with the label that corresponds to the end of the series with a larger lexical neighborhood, and listeners are biased to report more probable phonemes. Neighborhood and phoneme frequency effects are also found in a lexical decision task for clear, unambiguous tokens. Together with other work on higher-level influences on phoneme perception, these results indicate that phoneme perception is the result of an interaction between acoustic--phonetic information and the lexical knowledge of the individual, regardless of whether the target item is a word or not. [Work supported by NIDCD Grant No. R01 DC00219 to SUNY at Buffalo.]