Grunt communication in human infants (Homo sapiens).

Abstract

Laryngeally produced vocalizations termed grunts function communicatively in many species. The vocalizations and accompanying behavior of 5 human infants videorecorded monthly at the transition to speech were analyzed to determine the frequency, physiological basis, and functional status of grunt production, a phenomenon systematically studied for the first time here. Earliest grunts occurred accompanying movement or effort; next, they accompanied acts of focal attention; and finally they were used in communication. Communicative use was followed by the onset of referential ability in language. This sequence is interpreted in relation to the physiological basis of these vocalizations in respiratory function and to additional developmental variables observed in the children. The findings have implications for the transition to the communicative repertoire in other species in which laryngeal function contributes to communication.

Assessing vocal development in infants and toddlers

“…One explanation for this spike may be that vowels, already a wellestablished aspect of prelinguistic vocalizations prior to 13 months of age, were recruited for communicative purposes just before the onset of first words resulting in an unusually high frequency of occurrence. This explanation is underscored by findings of McCune et al (1996) that 'grunts' are often the first vocalizations to be used communicatively. It may, therefore, be useful to monitor increases in vowel frequency as a potential cue to the onset of word production in future investigations.…”

The Ontogenesis of Language Impairment in Autism: A Neuropsychological Perspective

“…As motor development proceeds, deictic gestures such as pointing emerge as critical additional elements in the communicative repertoire. Initial vocalizations are "vegetative" sounds, but later are produced concurrently with gestures (McCune et al 1996;Volterra et al 2005). Thereafter, gesture and speech co-evolve in a complex interrelationship that undergoes substantial change over time (Volterra et al 2005).…”

There Are No Back Vowels: The Laryngeal Articulator Model

“…Non-constricted vocalizations emerge only gradually over the months, appearing in systematic integration with pharyngeal sounds throughout prebabbling and into the babbling stage (Bettany 2004). These earliest vocalizations had been termed "grunts" (McCune et al 1996;Vihman 1996;McCune and Vihman 2001) but have come to be better understood phonetically since the mechanism of the laryngeal constrictor has been explored and elucidated in experimental phonetic research into the ways laryngeal and pharyngeal articulations are used in various strategically selected adult phonologies. Along with the pervasiveness of /A/ in phonologies (Maddieson 1984), the key role of retracted articulations in emergent infant phonetic production lends an importance to the pharyngeal vocal tract, which may have been previously overlooked in infant studies.…”