In the first year of life, infants' speech perception becomes attuned to the sounds of their native language. This process of early phonetic learning has traditionally been framed as phonetic category acquisition. However, recent studies have hypothesized that the attunement may instead reflect a perceptual space learning process that does not…

In learning language, children must discover how to interpret the linguistic significance of phonetic variation. On some accounts, receptive phonology is grounded in perceptual learning of phonetic categories from phonetic distributions drawn over the infant's sample of speech. On other accounts, receptive phonology is instead based on phonetic…

Infants rapidly learn language in their home environments. Between 6 and 12 months of age, infants' ability to process the building blocks of speech (i.e., phonetic information) develops quickly, and this ability predicts later language development. Typically, developing infants in a monolingual language environment rapidly tune in to the phonetic…

Language experience shapes infants' abilities to process speech sounds, with universal phonetic discrimination abilities narrowing in the second half of the first year. Brain measures reveal a corresponding change in neural discrimination as the infant brain becomes selectively sensitive to its native language(s). Whether and how bilingual…

Purpose: The function of child-directed speech has been debated for decades. This study examined the perceptual and acoustic characteristics of child- and adult-directed Cantonese tones to test the hyperarticulation and prosodic hypotheses that have been proposed to account for the acoustic modifications in child-directed speech. Method: Sixty-two…

Previous studies have suggested that the perception of vowels and consonants changes from language-universal to language-specific between 6 and 12 months of age. This report suggests that language-specific perception emerges even earlier for lexical tones. Experiment 1 tested English-learners' perception of Cantonese tones, replicating declines in…

In spontaneous conversations between adults, words are often pronounced with fewer segments or syllables than their citation forms. The question arises whether infant-directed speech also contains phonetic reduction. If so, infants would be presented with speech input that enables them to acquire reduced variants from an early age. This study…

How are languages learned, and to what extent are learning mechanisms similar in infant native-language (L1) and adult second-language (L2) acquisition? In terms of vocabulary acquisition, we know from the infant literature that the ability to discriminate similar-sounding words at a particular age does not guarantee successful word-meaning…

Both subjective impressions and previous research with monolingual listeners suggest that a foreign accent interferes with word recognition in infants, young children, and adults. However, because being exposed to multiple accents is likely to be an everyday occurrence in many societies, it is unexpected that such non-standard pronunciations would…

The influence of diet on cortical processing of syllables was examined at 3 and 6 months in 239 infants who were breastfed or fed milk or soy-based formula. Event-related potentials to syllables differing in voice-onset-time were recorded from placements overlying brain areas specialized for language processing. P1 component amplitude and latency…

Can infants, in the very first stages of word learning, use their perceptual sensitivity to the phonetics of speech while learning words? Research to date suggests that infants of 14 months cannot learn two similar-sounding words unless there is substantial contextual support. The current experiment advances our understanding of this failure by…

It is well attested that 14-month-olds have difficulty learning similar sounding words (e.g., bih/dih), despite their excellent phonetic discrimination abilities. By contrast, Rost and McMurray (2009) recently demonstrated that 14-month-olds' minimal-pair learning can be improved by the presentation of words by multiple talkers. This study…

Past research has uncovered a surprising paradox: Although 14-month-olds have exquisite phonetic discrimination skills (e.g., distinguishing [b] from [d]), they have difficulty using phonetic detail when mapping "novel" words to objects in laboratory tasks (confusing "bin" and "din"). While some have attributed infants' difficulty to immature word…

A shift from language-general to language-specific sound discrimination abilities has been largely attested in different populations of infants during the second half of the first year of life; however, data are still scarce regarding bilingual populations. Previous research with 4-, 8- and 12-month-old Catalan-Spanish bilingual infants had…

Infants at 1;2 demonstrate difficulty in accessing subtle phonetic information about newly learned word-object pairings (Stager & Werker, 1997). In this study, we examined whether or not infants can access subtle prosodic information such as lexical stress in a word learning task. We tested infants younger than 1;2 to see if they could learn two…