Читать книгу Lifespan Development - Tara L. Kuther - Страница 278

At birth, crying is the infant’s only means of communication. Infants soon learn to make many more sounds, like gurgles, grunts, and squeals. Between 2 and 3 months of age, infants begin cooing, making deliberate vowel sounds like “ahhhh,” “ohhhh,” and “eeeee.” Infants’ first coos sound like one long vowel. These vocal sounds are a form of vocal play; they are likely to be heard when babies are awake, alert, and contented. At the cooing stage, infants already use pauses that are consistent with the turn-taking pattern of spoken conversations. With age, the quality of coos changes to include different vowel-like sounds and combinations of vowel-like sounds (Owens, 2016). Babbling, repeating strings of consonants and vowels such as “ba-ba-ba” and “ma-ma-ma,” begins to appear at about 6 months of age.

Babies learn language by hearing others speak and by modifying their babbling in response to caregiver interactions.

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At first, babbling is universal. All babies do it, and the sounds they make are similar no matter what language their parents speak or in what part of the world they are raised. However, infants soon become sensitive to the ambient language around them, and it influences their vocalizations (Chen & Kent, 2010). In one study, French adults listened to the babbling of a French 8-month-old and a second 8-month-old from either an Arabic-speaking or a Cantonese-speaking family. Nearly three quarters of the time, the adults correctly indicated which baby in the pair was French (Boysson-Bardies et al., 1984). By the end of the first year, infants’ babbling sounds more like real speech as they begin to vary the pitch of their speech in ways that reflect the inflections of their native languages (Andruski, Casielles, & Nathan, 2013). For example, in spoken English, declarative sentences are characterized by pitch that falls toward the end of the sentence, whereas in questions, the pitch rises at the end of the sentence. Older babies’ babbling mirrors these patterns when they are raised by English-speaking parents, while babies reared with Japanese or French as their native languages show intonation patterns similar to those of the respective languages (Levitt et al., 1992). Longitudinal observations of infants raised in Catalan-speaking environments likewise show that their babbling shifts to mirror intonations in native speech (Esteve-Gilbert et al., 2013).

Language acquisition, as mentioned, is a socially interactive process: Babies learn by hearing others speak and by noticing the reactions that their vocalizations evoke in caregivers (Hoff, 2015; Kuhl, 2016). Social interaction elicits cooing, and infants modify their babbling in response to caregiver interactions (Tamis-LeMonda, Kuchirko, & Song, 2014). For example, when mothers of 9½-month-old infants speak in response to their infants’ babbling, infants restructure their babbling, changing the phonological pattern of sounds in response to their mothers’ speech (Goldstein & Schwade, 2008). Babbling repertoires reflect infants’ developing morphology and are a foundation for word learning (Ramsdell, Oller, Buder, Ethington, & Chorna, 2012). Language development follows a predictable pattern.