ABSTRACT
This chapter considers earlier conceptualizations of second language learning based on a behaviorist view in which the major driving force of language learning was the language to which learners were exposed. The chapter focuses on descriptions and functions of input, beginning with a brief description of findings from the child language literature because this literature informs much of the research in second language. Research on input modifications in other cultures suggests that the kinds of modifications common in Western middle-class families are far from the norm. In the second language context, modifications to non-native speakers, or non-native directed speech, seem more uniform because most studies report speech within a Western context. Within the second language literature, the Krashen's monitor model itself initially had a great impact and spawned a number of empirical studies. There are five basic hypotheses in this model, the acquisition-learning hypothesis, the natural order hypothesis, the monitor hypothesis, the input hypothesis, and the affective filter hypothesis.
