Language Development in Infancy

All 6 Terms & Definitions

Categorical Speech Perception

The tendency to perceive speech sounds as belonging to discrete categories rather than as points on a continuous physical dimension. Demonstrated in infants using the high-amplitude sucking habituation paradigm: infants treat a shift across a phoneme boundary (e.g., /p/ to /b/) as more salient than an equally large shift within a category. Initially universal, it narrows to native-language contrasts by 10–12 months.

Statistical Learning

The implicit extraction of regularities — particularly transitional probabilities between adjacent syllables — from the input stream. Saffran, Aslin, and Newport (1996) showed that 8-month-old infants segment words from a continuous artificial language after 2 minutes of exposure, using the fact that syllables within words follow each other with higher probability than syllables across word boundaries.

Canonical Babbling

Babbling that conforms to syllabic structure — repeated consonant-vowel sequences such as "bababa" or "mamama." Emerges between 6 and 10 months and is considered a universal milestone of pre-linguistic development. Its onset reflects maturation of the vocal tract and oro-motor control, and its phonological content is increasingly shaped by the ambient language.

Joint Attention

The capacity to co-ordinate visual attention with a social partner toward a shared external object or event, achieved through gaze following, pointing, and referential looking. Emerges reliably around 9–12 months. Functions as the scaffold on which word learning is built: words are typically learned in joint attention episodes in which caregiver and child share a referent.

Child-Directed Speech (Motherese)

The register adults spontaneously adopt when talking to infants: higher pitch, exaggerated prosodic contours, slower pace, simpler grammar, and repetition. Infants prefer it to adult-directed speech. It may facilitate phoneme discrimination, word segmentation, and syntactic learning by making the acoustic properties of the language more salient.

Perceptual Narrowing

The developmental process by which infants' initially universal sensitivity to phoneme contrasts narrows to the contrasts relevant to their native language. By 10–12 months, infants who once discriminated Hindi retroflex consonants or Zulu click consonants no longer do so reliably. Reflects neural tuning driven by statistical exposure to the ambient language.