12.7: Native Language Magnet Theory Expanded (NLM-e)
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Native Language Magnet Theory of Language Acquisition
Young children are born ready to learn their native language or languages rapidly and with relative ease, following similar developmental paths regardless of culture or language. In this way, young infants are “citizens of the world” (Kuhl, 2004) because they are able to phonetically distinguish between the sounds of all the world’s languages and acquire any language they are exposed to. Phonetics refers to how the sounds in a language are made and what they actually sound like. Infants are very good at noticing phonetic differences, and they can tell the difference between all kinds of different sounds from many different languages. But this ability changes within the first year of life. To acquire a language, infants must be able to discover which specific phonetic distinctions will be utilized in their native language. The early ability of young infants to phonetically distinguish between the sounds of different languages begins to diminish as repeated exposure to one’s native language leads to infants becoming “culture-bound listeners”, now only able to distinguish the sounds in their native language (Kuhl, 2004). For example, at six months of age, English-learning babies are about 80-90% successful at noticing phonetic differences in English, in Hindi, and in Salish (Werker & Tees, 1984). But by ten months of age, their success rate drops to about 50-60%, and by the time they are one year old, they are only about 10-20% successful at hearing the phonetic differences in Hindi and Salish. The theory of NLM-e explains the narrowing of infant speech perception and the subsequent growth of native language abilities. [1] [2]
NLM-e proposes that young infants’ universal early speech perception ability narrows with language experience as the brain neurally commits to the child’s native language, thereby fostering the language acquisition process. There are five basic principles of NLM-e (Kuhl et al., 2008):
Distributional patterns and infant-directed language are agents of change.
In order to comprehend language infants first have to acquire the sound inventory of a given language, that is, learn how many and which speech sounds are functionally distinct units. When a caregiver talks with an infant, what the infant hears is a long strand of continuous language sounds. How does an infant learn the individual words within a speech stream? One of the mechanisms they use is distributional learning, which refers to learning by simply listening to the frequency distributions of the speech sounds in language. Different languages have different distributional sound patterns, as some sounds are more likely to frequently be heard together than others. Infants as young as 2 months of age are sensitive to the distributional sound patterns in language (Maye, Werker, & Gerken, 2002; Wanrooij, Boersma, & van Zuijen, 2014). As research suggests distributional learning is one of the mechanisms by which infants start to acquire the phonemes of their native language, NLM-e includes it as an important agent of change. [3] When adult caregivers talk with infants and toddlers, they tend to use a different speech style, often referred to as infant-directed speech, that includes higher pitch, greater pitch range, and longer pauses between words, (Fernald et al.,1989; Outters et al., 2020). Infants prefer to listen to infant-directed speech over adult-directed speech at birth (Cooper & Aslin, 1990), as well as later in infancy (Fernald, 1985; Werker & McLeod, 1989). When listening to infant-directed speech, compared to adult-directed speech, infants are better able to discriminate speech sounds (Karzon, 1985; Trainor & Desjardins, 2002), more efficiently segment words from continuous speech (Thiessen, Hill & Saffran, 2005), demonstrate better long-term memory for words (Singh et al., 2009), and learn new words more effectively (Graf Estes & Hurley, 2013; Ma et al., 2011). As a result, NLM-e proposes that infant-directed speech is an agent of change because it helps infants phonetically discriminate language sounds as well as helps them acquire their native language. [4] [5]
Language exposure produces neural commitment that affects future learning.
Adults who either heard or spoke an additional language as a child have better perception and production abilities when relearning that childhood language later in life. Thus, exposure to a language within the first year of life provides sustained benefit to learners as language exposure in infancy leads to neural commitment. Furthermore, the benefits of early non-native language exposure begins to be observed almost immediately. For example, infants’ speech perception abilities change with as little as 5 hours of exposure to a second language (Kuhl et al., 2003; Conboy & Kuhl, 2011) and remain changed even a month after exposure has been discontinued (Sundara et al., 2020). [6]
Social interaction influences early language learning at the phonetic level.
In a series of studies Kuhl and colleagues have shown the significance of social interaction on phonetic learning. When English-monolingual infants were exposed to Mandarin Chinese through a “live condition” (experimenter directly interacting with the infant during learning) the infants demonstrated phonetic learning of the foreign language; however, exposure to Mandarin Chinese from a video did need lead to phonetic learning (Kuhl, Tsao & Liu, 2003). When these same Mandarin Chinese videos were presented to infants over an interactive touchscreen device, greater phonetic learning occurred for infants paired together, compared to infants without a social partner (Lytle, Garcia-Sierra & Kuhl, 2018). This line of research highlights the importance social interactions have on language learning at the phonetic level. [7]
Early speech perception predicts language growth.
NLM-e proposes that early language perception abilities (such as phonetic perception) is related to later language abilities. Indeed research has shown this association. Six month old infants’ speech perception ability is related, longitudinally, to language development at 13 months, 16 months and 24 months of age (Tsao, Liu & Kuhl, 2004). More recent research is finding this association lasts throughout early childhood as infants with greater speech perception abilities at 11 months of age demonstrated greater grammatical abilities as six year olds (Zhao et al., 2021).
The perception-production link is forged developmentally.
Early phonetic perception abilities are related to later language production abilities (Zhao et al., 2021). The connection between language perception and language production is built through the experiences of language exposure and infant vocalizations. Through language exposure, infants establish mental maps to represent the specific sounds of their native language. Through vocalization, infants relate the articulatory properties they use to create various sounds, to the sounds they hear themselves produce and then relate that to the language sounds they have mapped out from adult language exposure. This developmental perspective on language acquisition suggests that early language perception is critical and that language production relies upon perceptual abilities
[1] Psycholinguistics/Theories and Models of Language Acquisition. CC BY-SA 3.0
[2] Essentials of Linguistics by Catherine Anderson is licensed under CC by 4.0
[3] Chládková, K., & Šimáčková, Š. (2021). Distributional learning of speech sounds: An exploratory study into the effects of prior language experience. Language Learning, 71(1), 131-161. CC by 4.0
[4] Outters, V., Schreiner, M. S., Behne, T., & Mani, N. (2020). Maternal input and infants’ response to infant‐directed speech. Infancy, 25(4), 478-499. CC by 4.0
[5] Byers-Heinlein et al., (2021). A Multilab Study of Bilingual Infants: Exploring the Preference for Infant-Directed Speech. Advances in Methods and Practices in Psychological Science, 4(1), 2515245920974622. CC by 4.0
[6] Sundara, M., Ward, N., Conboy, B., & Kuhl, P. K. (2020). Exposure to a second language in infancy alters speech production. Bilingualism: Language and Cognition, 23(5), 978-991. CC by 4.0
[7] Li, P., & Jeong, H. (2020). The social brain of language: grounding second language learning in social interaction. npj Science of Learning, 5(1), 1-9. CC by 4.0