What Do Caregivers Tell Us about Infant Babbling?

Phonetic repertoires in babbling are an important marker of prelinguistic development. Typical phonetic development, however, is difficult to identify given variability within and across infants. Prior to 18 months of infant age, caregiver report of prelinguistic vocal development is often an important part of clinical practice for early intervention. As a first step toward understanding the utility of caregiver report of babbling, the purpose of this exploratory study was to determine how the phonetic makeup of sounds reported by caregivers in infant babbling would develop, in particular comparison to markedness theory and established norms. In a longitudinal design, caregiver report was tracked through weekly interviews from 7 to 18 months of infant age (N = 15). Reports were phonetically transcribed and examined in terms of the number of utterances; place, manner, and voicing for consonants; and tongue position for vowels. In general, the number of utterances and phonetic segments reported by caregivers increased significantly with infant age (p < .05) and phonetic feature patterns were similar to what one would expect in the vocal development of English-learning infants. Results support the notion that caregiver report of infant vocalizations may provide a valuable means for describing early infant babbling development

Differing Roles of the Face and Voice in Early Human Communication: Roots of Language in Multimodal Expression

Seeking roots of language, we probed infant facial expressions and vocalizations. Both have roles in language, but the voice plays an especially flexible role, expressing a variety of functions and affect conditions with the same vocal categories - a word can be produced with many different affective flavors. This requirement of language is seen in very early infant vocalizations. We examined the extent to which affect is transmitted by early vocal categories termed protophones (squeals, vowel-like sounds, and growls) and by their co-occurring facial expressions, and similarly the extent to which vocal type is transmitted by the voice and co-occurring facial expressions. Our coder agreement data suggest infant affect during protophones was most reliably transmitted by the face (judged in video-only), while vocal type was transmitted most reliably by the voice (judged in audio-only). Voice alone transmitted negative affect more reliably than neutral or positive affect, suggesting infant protophones may be used especially to call for attention when the infant is in distress. By contrast, the face alone provided no significant information about protophone categories. Indeed coders in VID could scarcely recognize the difference between silence and voice when coding protophones in VID. The results suggest that partial decoupling of communicative roles for face and voice occurs even in the first months of life. Affect in infancy appears to be transmitted in a way that audio and video aspects are flexibly interwoven, as in mature language

Differing Roles of the Face and Voice in Early Human Communication: Roots of Language in Multimodal Expression

Seeking roots of language, we probed infant facial expressions and vocalizations. Both have roles in language, but the voice plays an especially flexible role, expressing a variety of functions and affect conditions with the same vocal categories—a word can be produced with many different affective flavors. This requirement of language is seen in very early infant vocalizations. We examined the extent to which affect is transmitted by early vocal categories termed “protophones” (squeals, vowel-like sounds, and growls) and by their co-occurring facial expressions, and similarly the extent to which vocal type is transmitted by the voice and co-occurring facial expressions. Our coder agreement data suggest infant affect during protophones was most reliably transmitted by the face (judged in video-only), while vocal type was transmitted most reliably by the voice (judged in audio-only). Voice alone transmitted negative affect more reliably than neutral or positive affect, suggesting infant protophones may be used especially to call for attention when the infant is in distress. By contrast, the face alone provided no significant information about protophone categories. Indeed coders in VID could scarcely recognize the difference between silence and voice when coding protophones in VID. The results suggest that partial decoupling of communicative roles for face and voice occurs even in the first months of life. Affect in infancy appears to be transmitted in a way that audio and video aspects are flexibly interwoven, as in mature language