Cross-Language Analysis of Phonetic Units in Language Addressed to Infants

Abstract

In the early months of life, infants acquire information about the phonetic properties of their native language simply by listening to adults speak. The acoustic properties of phonetic units in language input to young infants in the United States, Russia, and Sweden were examined. In all three countries, mothers addressing their infants produced acoustically more extreme vowels than they did when addressing adults, resulting in a "stretching" of vowel space. The findings show that language input to infants provides exceptionally well-specified information about the linguistic units that form the building blocks for words.

Asymmetries in vowel perception

“…In addition, data reported by Bernstein Ratner (1984) show that the peripheral vowels, /i/, / /, /u/ and /ae/, are clarified in speech directed to pre-linguistic infants, such that these vowels are produced with little or no acoustic overlap with other vowels. Kuhl et al (1997) showed that the vowel space defined by /i/, / a/ and /u/ is expanded in speech directed to 6-month olds such that these corner vowels occur in a hyperarticulated form (other vowels were not analyzed); this was observed regardless of whether mothers were speaking English, Swedish or Russian. Presently, two months is the youngest age at which we have evidence for asymmetries in human vowel perception (Swoboda et al, 1978).…”

Brain and cognitive evolution: Forms of modularity and functions of mind.

“…Language is one well-known example whereby the features of individual languages (e.g., phonemes) are accommodated within what appear to be inherent neural, perceptual, and cognitive constraints such that individuals develop the language to which they are exposed (R. Brown, 1973;Kuhl, 1994;Kuhl et al, 1997;Pinker, 1994). Aspects of this accommodation appear to involve the exoskeleton form of plasticity (e.g., for phoneme recognition) and occur as an experience-expectant feature of language development (Doupe & Kuhl, 1999).…”

Infant-directed speech as a window into the dynamic nature of phonology

“…It has been argued that the distinct phonetic categories in IDS serve to provide the infant with input that is optimized for learning certain aspects of the linguistic system (Kuhl et al 1997;de Boer and Kuhl 2003;Kirchhoff and Schimmel 2005). These hypotheses have in common a vision of IDS as an essentially listener-oriented speech style, in which the speaker expends additional effort in order to maximize the information content in the signal, making the infant listener's task easier.…”

“…Research on IDS has shown that phonetic categories in IDS tend to be more distinct (Malsheen 1980;Masataka 1992;Andruski and Kuhl 1996;Kuhl et al 1997;Burnham et al 2002;Liu et al 2007;Cristià 2010) when compared to ADS. It has been argued that the distinct phonetic categories in IDS serve to provide the infant with input that is optimized for learning certain aspects of the linguistic system (Kuhl et al 1997;de Boer and Kuhl 2003;Kirchhoff and Schimmel 2005).…”

“…An extensive body of research has examined in what ways IDS differs from adult-directed speech (ADS) among the world's languages (see Soderstrom 2007 for a review). For example, IDS is characterized by overall higher pitch (Ferguson 1964;Fernald and Simon 1984), a greater pitch range (Fernald and Simon 1984), larger pitch peaks on focused words (Fernald and Mazzie 1991), slower speech rate (Bryant and Barrett 2007), and more distinct phonetic categories (Malsheen 1980;Masataka 1992;Andruski and Kuhl 1996;Kuhl et al 1997;Burnham et al 2002;Liu et al 2007;Cristià 2010) when compared to ADS. In the literature, these characteristics of IDS have been argued to play important roles in communication between infants and caregivers, such as capturing the infants' attention, communicating affect, and facilitating the infants' language development (e.g., Fernald 1989;Kitamura et al 2002).…”