Prosody, or the intonation contours of speech, conveys emotion and intention to the listener
and provides infants with an early basis for detecting meaning in speech. Infant-directed
speech (IDS) is characterized by exaggerated prosody, slower tempo, and elongated
pauses, all amodal properties detectable across the face and voice. Although speech is an
audiovisual event, it has been studied primarily as a unimodal auditory stream without the
synchronized dynamic face of the speaker. According to the intersensory redundancy …