Input filters in second language acquisition

This paper reviews a variety of restrictions (input filters) on the conversion of input to intake and thence to acquisition. These filters are internal characteristics of the learner which seem to interfere with the ability to make use of L2 input for acquisition, even when that input seems, on the surface, to be appropriate and plentiful. Three sorts of filters are examined: affective filters, auditory/phonological filters, and cognitive filters. In the third category, three kinds of cognitive filters are discussed: (a) overload or conflict in the processing systems, (b) developmental filters, and (c) effects of previously learned languages. The discussion focuses on the role of instruction and feedback in making input more accessible to classroom learners and guiding them to perceive the difference between interlanguage patterns and those of the target language.