Constructing a Proto-Lexicon: An Integrative View of Infant Language Development

Abstract

Infants begin learning the phonological structure of their native language remarkably early and use this information to extract word-sized chunks from the speech signal. While acquiring the language-specific segmentation strategies appropriate for their native language, infants are simultaneously beginning to form word-object pairings and learning which sound contrasts are meaningful in the native language. They are also working out how to assign words to word classes, paying attention to the use and placement of function words, and learning how speakers of the language string words together to form sensible grammatical utterances. Amazingly, infants tackle all of these tasks simultaneously, with success in each of these domains dependent on success in the others. This review focuses on infants' discovery of word forms in speech, their construction of a proto-lexicon, and the development of linguistic knowledge during their first year and a half of life. By discussing the development of lexical knowledge in relation to other aspects of linguistic development, I demonstrate the advantages of an integrative approach to understanding early language acquisition.

Early phonology revealed by international adoptees' birth language retention

“…Knowing the phoneme categories can obviously aid compilation of a vocabulary (23), and knowing words can aid definition of the phoneme categories (24,25). Thus, when the infant brain has matured to the point at which sound/word pairings are being tentatively assessed, for instance, on the basis of statistically likely clusterings of syllables (61), these mutually assisting processes cooperate to produce the rapid progress toward each goal, vocabulary and phoneme repertoire, that we see in the second half of the first year (26). The phonological knowledge that has been built up in the first 6 mo can effectively come into its own in the second 6 mo by delivering useful hypotheses (about constraints on word formation or about potential phoneme repertoire membership) that can be verified or rejected on the basis of the developing vocabulary and inventory.…”

“…The acquisition of an initial vocabulary and of the native phoneme repertoire in the same general time period made for an attractive scenario in which the two activities were seen as linked, (i) in that mastering the phoneme repertoire gave information about which different sequences were actually different words rather than alternative ways of saying the same word (23), (ii) in that compiling a repertoire of words gave information about ways in which words could minimally differ (24,25), or (iii) in that the two processes acting together ensured optimal progress toward successful speech processing (26). However, recent studies have pushed the threshold of word recognition to an earlier time point: segmentation of running speech (27,28) and recognition of words referring to familiar people and concepts (29,30) have been demonstrated in infants of 6 mo or younger, and neural precursors of word recognition have been observed even at 3 mo (31).…”

What Constitutes a Phrase in Sound-Based Music? A Mixed-Methods Investigation of Perception and Acoustics

“…Second, such studies suggest that a few features are very important for the learning of word-boundaries. A detailed review of infant language development [40] points out that spoken words run into each other, blurring word boundaries; a blurring, we argue, that may be similar to the continuum between note- and sound-based music. Once our native language is learnt, we begin to sustain the illusion that boundaries are clear [35].…”

“…Once our native language is learnt, we begin to sustain the illusion that boundaries are clear [35]. Learning the segmentation in the first place (often described as the 'bootstrapping problem') is largely dependent on developing relative weightings for the relevance of pause duration, pitch, and pre-boundary lengthening [40, 41]. Pause does not refer to silence, but rather the relative length of time between increments of acoustic intensity.…”

Integrating Orthographic and Phonological Knowledge in Early Readers: Implicit and Explicit Knowledge

“…Phonological knowledge-the understanding of the sounds of a language-in particular has long been considered to develop even before birth [15,16]. Importantly, many researchers have historically considered orthographic knowledge to stem directly from phonological knowledge, such that researchers once considered early orthographic representation (i.e., spellings) as random until it became linked with early phonological knowledge [13].…”