Much of second language theory is influenced by cognitive psychology. Concepts such as interlanguage view language learning as an internal mental process, and the learner as separate from the setting in which he learns a language.
A sociocultural perspective on second language learning, however, views child language learning as about making meaning in collaboration with other users of the language.
Heavily influenced by Lev Vygotsky. The learner acquires new language through the joint construction of language between a learner and a more expert user of the language.