Language Acquisition & Thought

All 12 Terms & Definitions

Language Acquisition Device (LAD)

Chomsky's theoretical construct for the innate language-learning capacity that constrains possible grammars and enables rapid acquisition from impoverished input.

Universal Grammar (UG)

The set of innate constraints on possible human languages — proposed by Chomsky to explain why all languages share abstract structural properties (e.g., structure-dependence, recursion).

Poverty of the stimulus

Children acquire grammatical knowledge (e.g., structure-dependence) that is not consistently present in their input, suggesting innate grammatical constraints rather than purely data-driven learning.

Critical period

A developmental window during which language acquisition is maximally efficient; after puberty, native-like proficiency in a second language becomes very difficult (Johnson & Newport, 1989).

Fast mapping

Children's ability to form an initial word-to-concept link from minimal exposure — a single brief encounter with a new word (Carey & Bartlett, 1978); underlies the vocabulary spurt around 18 months.

Overregularisation

Applying a regular grammatical rule to irregular forms ("goed", "mouses") — evidence of rule extraction rather than rote learning; produces U-shaped development (correct → error → correct).

Statistical learning

Sensitivity to transitional probabilities between syllables in the speech stream, enabling word segmentation without explicit instruction (Saffran et al., 1996).

Infant-directed speech (IDS)

The speech register used by caregivers with infants — higher pitch, exaggerated intonation, simpler syntax, slower tempo — which attracts infant attention and facilitates language learning.

Linguistic relativity

The weak Sapir-Whorf hypothesis: language influences (but does not determine) cognitive processes such as colour discrimination (Winawer et al., 2007) and temporal reasoning (Boroditsky, 2001).

Sapir-Whorf hypothesis

The claim that language shapes thought; exists in a strong form (linguistic determinism — refuted) and a weak form (linguistic relativity — supported with caveats).

Inner speech

Vygotsky's term for internalized, condensed, predicative self-directed speech that develops from social external speech through the intermediate stage of private (audible) speech.

Home sign

Structured gestural communication systems spontaneously developed by deaf children who are not exposed to conventional sign language, showing an innate drive to impose linguistic structure on communication.