| Term | Definition |
| acquisition-learning hypothesis | acquisition is a subconsious process that results in acquired competence. Learning is a conscious process that involves knowing the rules and being aware of them (and being able to talk about them). Krashen says that the knowledge acquired remains internalized differently (and cannot cross over to the other means). |
| the 5 hypotheses of the monitor model | acquisition-learning, natural order, monitor, input, and affective filter |
| comprehensible input | a second language input just beyond the learner’s current second language competence, in terms of syntactic complexity |
| i + 1 | If a learner’s current competence is i then comprehensible input is i + 1, the next step in the developmental sequence. Learners move along the developmental continuum by receiving comprehensible input |
| the value of foreigner talk and motherese | Simplified language. NS + NNS alter their language with each other to facilitate comprehension, providing i + 1 for the learner. Re: motherese, children seem to be unaffected by ungrammatical input. |
| input hypothesis criticisms | how to define i or i + 1? Not based on empirical evidence. What is a sufficient quantity of input? How to define understanding? How does understanding translate into acquisition? |