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Despite their potential significance for later linguistic outcomes, early aspects of vocalization had been seriously undervalued in the past, and thus, minimally investigated until relatively recently. The present article sets out to critically examine existing evidence to: i) ascertain whether vocalization frequency (volubility) posits a plausible marker of cochlear implantation success in infancy, and ii) determine the clinical usefulness of post-implementation vocalization frequency data in predicting later language development. Only recent peer-reviewed articles with substantial impact on vocalization growth during the first year of life, examining sound production characteristics of normally hearing (NH) and hearing impaired infants fitted with cochlear implantation (CI) were mentioned. Recorded differences in linguistic performance among NH and CI infants are typically attributed to auditory deprivation. Infants who have undergone late CI, produce fewer syllables (low volubility) and exhibit late-onset babbling, especially those who received their CIs at the age of 12 months or thereafter. Contrarily, early recipients (before the 12-month of age) exhibit higher volubility (more vocalizations), triggered from CI-initiated auditory feedback. In other words, early CI provides infants with early auditory access to speech sounds, leading to advanced forms of babbling and increased post-implementation vocalization frequency. Current findings suggest vocalization frequency as a plausible criterion of the success of early CI. It is argued that vocalization frequency predicts language development and affects habilitation therapy.

Despite their potential significance for later linguistic outcomes, early aspects of vocalization had been seriously undervalued in the past, and thus, minimally investigated until relatively recently. The present article sets out to critically examine existing evidence to: i) ascertain whether vocalization frequency (volubility) posits a plausible marker of cochlear implantation success in infancy, and ii) determine the clinical usefulness of post-implementation vocalization frequency data in predicting later language development. Only recent peer-reviewed articles with substantial impact on vocalization growth during the first year of life, examining sound production characteristics of normally hearing (NH) and hearing impaired infants fitted with cochlear implantation (CI) were mentioned. Recorded differences in linguistic performance among NH and CI infants are typically attributed to auditory deprivation. Infants who have undergone late CI, produce fewer syllables (low volubility) and exhibit late-onset babbling, especially those who received their CIs at the age of 12 months or thereafter. Contrarily, early recipients (before the 12-month of age) exhibit higher volubility (more vocalizations), triggered from CI-initiated auditory feedback. In other words, early CI provides infants with early auditory access to speech sounds, leading to advanced forms of babbling and increased post-implementation vocalization frequency. Current findings suggest vocalization frequency as a plausible criterion of the success of early CI. It is argued that vocalization frequency predicts language development and affects habilitation therapy. [ABSTRACT FROM AUTHOR]

Children’s speech development begins in infancy. The pattern of this development has been explored in studies over a number of years using a range of research methodology and approaches to investigation. A systematic review of the existing literature was carried out to determine the collective contribution of this literature to our understanding of early vocalizations and babbling through the period 9 to 18 months. Eight bibliographic databases were searched as well as the Cochrane library. Thirteen studies were identified for inclusion, which were mostly longitudinal observational case series. The review identified progressive increases in the complexity and volume of infants’ early vocalizations through the period. It also found a broad order of phonological acquisition. Although the studies in this review demonstrated marked individual variation, the review provides indicative patterns of development which can be used as a basis to explore relationships with later speech development in future studies. [ABSTRACT FROM AUTHOR]