Updating the interlanguage hypothesis
By describing the ways in which learner language conforms to universal linguistic norms, interlanguage research has contributed greatly to our understanding of linguistic universals in second-language acquisition.
Before the interlanguage hypothesis rose to prominence, the principal theory of second-language (L2) development was contrastive analysis.
An interlanguage is an idiolect that has been developed by a learner of a second language (or L2) which preserves some features of their first language (or L1), and can also overgeneralize some L2 writing and speaking rules.
These two characteristics of an interlanguage result in the system's unique linguistic organization.
Although this was initially done to validate the claims of contrastive analysis, researchers found that many learner behaviours could not be easily explained by transfer from learners' L1 to their L2.Interlanguage can be variable across different contexts; for example, it may be more accurate, complex and fluent in one domain than in another.To study the psychological processes involved one can compare the interlanguage utterances of the learner with two things: It is possible to apply an interlanguage perspective to a learner's underlying knowledge of the target language sound system (interlanguage phonology), grammar (morphology and syntax), vocabulary (lexicon), and language-use norms found among learners (interlanguage pragmatics).For example, they may deliberately choose to address a non-target form like "me no" to an English teacher in order to assert identity with a non-mainstream ethnic group.The most important psychological factor is usually regarded as attention to form, which is related to planning time.
This type of variability seems to be most common among beginning learners, and may be entirely absent among the more advanced.