ABSTRACT
Understanding how language acquisition occurs requires both a detailed description of the initial capacities of first language learners and an accurate characterization of the nature of the linguistic input they receive, Neither task is trivial. The researcher investigating the initial capacities faces many obstacles in determining the range of infants’ cognitive and perceptual abilities. Devising appropriate methods to assess the perceptual capacities of infants has been diffcult enough. How to delineate fully the nature of any abstract cognitive constraints that enter into language learning is far from clear. There are also serious diffculties to surmount in describing the nature of the effective linguistic input that learners receive. Not only are there practical problems in trying to record and transcribe the real input that learners receive, but there is the added diffculty in determining which aspects of the input are attended to and encoded by learners. Indeed, characterizing the latter requires some knowledge of learners’ perceptual and cognitive capacities.
