/ Dictionary / Index L language acquisition device: Meaning and Definition of Find definitions for: lan'guage acquisi'tion device" Pronunciation: [key] — Psycholinguistics. Psycholinguistics. a hypothesized innate mental faculty present in infants that enables them to construct and internalize the grammar of their native language on the basis of the limited and fragmentary language input to which they are exposed. Abbr.: LAD Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. language language arts Related Content Daily Word Quiz: hale Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language