Using Mandarin Chinese, a "tone language" in which the pitch contours of syllables differentiate words, the authors examined the acoustic modifications of infant-directed speech (IDS) at the syllable level to test 2 hypotheses: (a) the overall increase in pitch and intonation contour that occurs in IDS at the phrase level would not distort…

In tone languages, the identity of a word depends on its tone pattern as well as its phonetic structure. The primary cue to tone identity is the fundamental frequency (F0) contour. Two experiments explore how listeners perceive Mandarin monosyllables in which all or part of the F0 information has been neutralized. In Experiment 1, supposedly…