Preterm and full term infant vocalization and the origin of language.

How did vocal language originate? Before trying to determine how referential vocabulary or syntax may have arisen, it is critical to explain how ancient hominins began to produce vocalization flexibly, without binding to emotions or functions. A crucial factor in the vocal communicative split of hominins from the ape background may thus have been copious, functionally flexible vocalization, starting in infancy and continuing throughout life, long before there were more advanced linguistic features such as referential vocabulary. 2-3 month-old modern human infants produce "protophones", including at least three types of functionally flexible non-cry precursors to speech rarely reported in other ape infants.

Language Origins Viewed in Spontaneous and Interactive Vocal Rates of Human and Bonobo Infants.

From the first months of life, human infants produce "protophones," speech-like, non-cry sounds, presumed absent, or only minimally present in other apes. But there have been no direct quantitative comparisons to support this presumption. In addition, by 2 months, human infants show sustained face-to-face interaction using protophones, a pattern thought also absent or very limited in other apes, but again, without quantitative comparison.

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.

An unsettled debate: Key empirical and theoretical questions are still open.

Debates about neonatal imitation remain more open than Keven & Akins (K&A) imply. K&A do not recognize the primacy of the question concerning differential imitation and the links between experimental designs and more or less plausible theoretical assumptions. Moreover, they do not acknowledge previous theorizing on spontaneous behavior, the explanatory power of entrainment, and subtle connections with social cognition.

Babbling development as seen in canonical babbling ratios: A naturalistic evaluation of all-day recordings.

Canonical babbling (CB) is critical in forming foundations for speech. Research has shown that the emergence of CB precedes first words, predicts language outcomes, and is delayed in infants with several communicative disorders. We seek a naturalistic portrayal of CB development, using all-day home recordings to evaluate the influences of age, language, and social circumstances on infant CB production.

Neonatal Imitation: Theory, Experimental Design, and Significance for the Field of Social Cognition.

Neonatal imitation has rich implications for neuroscience, developmental psychology, and social cognition, but there is little consensus about this phenomenon. The primary empirical question, whether or not neonatal imitation exists, is not settled. Is it possible to give a balanced evaluation of the theories and methodologies at stake so as to facilitate real progress with respect to the primary empirical question? In this paper, we address this question.

Subtlety of Ambient-Language Effects in Babbling: A Study of English- and Chinese-Learning Infants at 8, 10, and 12 Months.

Prior research on ambient-language effects in babbling has often suggested infants produce language-specific phonological features within the first year. These results have been questioned in research failing to find such effects and challenging the positive findings on methodological grounds. We studied English- and Chinese-learning infants at 8, 10, and 12 months and found listeners could not detect ambient-language effects in the vast majority of infant utterances, but only in items deemed to be words or to contain canonical syllables that may have made them sound like words with language-specific shapes.

Emergence of Functional Flexibility in Infant Vocalizations of the First 3 Months.

Functional flexibility, as manifest in the use of any word or sentence to express different affective valences on different occasions, is required in linguistic communication and can be said to be an infrastructural property of language. Early infant vocalizations (protophones), believed to be precursors to speech, occur in the first month and are functionally different from non-speech-like signals (e.g.