Processing of illegal consonant clusters: a case of perceptual assimilation?

Evidence is presented for a perceptual shift affecting consonant clusters that are phonotactically illegal, albeit pronounceable, in French. They are perceived as phonetically close legal clusters. Specifically, word-initial /dl/ and /tl/ are heard as /gl/ and /kl/, respectively. In 2 phonemic gating experiments, participants generally judged short gates--which did not yet contain information about the 2nd consonant /l/--as being dental stops. However, as information for the /l/ became available in larger gates, a perceptual shift developed in which the initial stops were increasingly judged to be velars. A final phoneme monitoring test suggested that this kind of shift took place on-line during speech processing and with some extratemporal processing cost. These results provide evidence for the automatic integration of low-level phonetic information into a more abstract code determined by the native phonological system.

Speech versus nonspeech in pitch memory.

The memory trace of the pitch sensation induced by a standard tone (S) can be strongly degraded by subsequently intervening sounds (I). Deutsch [Science 168, 1604-1605 (1970)] suggested that the degradation is much weaker when the I sounds are words than when they are tones. In Deutsch's study, however, the pitch relations between S and the I words were not controlled. The first experiment reported here was similar to that of Deutsch except that the speech and nonspeech stimuli used as I sounds were matched in pitch. The speech stimuli were monosyllabic words derived from recordings of a real voice, whereas the nonspeech stimuli were harmonic complex tones with a flat spectral profile. These two kinds of I sound were presented at a variable pitch distance (delta-pitch) from the S tone. In a same/different paradigm, S had to be compared with a tone presented 6 s later; this comparison tone could be either identical to S or shifted in pitch by +/- 75 cents. The nature of the I sounds (spoken words versus tones) affected discrimination performance, but markedly less than did delta-pitch. Performance was better when delta-pitch was large than when it was small, for the speech as well as nonspeech I sounds. In a second experiment, the S sounds and comparison sounds were spoken words instead of tones. The differences to be detected were restricted to shifts in fundamental frequency (and thus pitch), the other acoustic attributes of the words being left unchanged. Again, discrimination performance was positively related to delta-pitch. This time, the nature of the I sounds (words versus tones) had no significant effect. Overall, the results suggest that, in auditory short-term memory, the pitch of speech sounds is not stored differently from the pitch of nonspeech sounds.

Beginnings of prosodic organization: intonation and duration patterns of disyllables produced by Japanese and French infants.

In this study, some prosodic aspects of the disyllabic vocalizations (both babbling and words) produced by four French and four Japanese children of about 18 months of age, are examined. F0 contour and vowel durations in disyllables are found to be clearly language-specific. For French infants, rising F0 contours and final syllable lengthening are the rule, whereas falling F0 contours and absence of final lengthening are the rule for Japanese children. These results are congruent with adult prosody in the two languages. They hold for both babbling and utterances identified as words. The disyllables produced by the Japanese infants reflect adult forms not only in terms of global intonation patterns, but also in terms of tone and duration characteristics at the lexical level.