Interlanguage refers to a learner's language that has features of both their first and second languages. It was coined by Selinker and has five principles including language transfer and overgeneralization. Interlanguage is permeable, dynamic, and systematic, with three key features - it incorporates aspects of the learner's other languages, it changes and develops over time, and it has its own internal structure and logic.

2. Based on mentalist account of theory.
The term interlanguage refers to
a form of language having
features of both the learner’s L1
and L2.

3. Selinker:
coined the term
Suggested 5 principles
1.Language transfer
2.Overgeneralization
3.Transfer of training
4.Strategies of L2 learning
5.Strategies of L2 communication.
Talked about target language continuum.

4. Three principal features of Interlanguage:
* Language-Learner Language is Permeable
* Language-Learner Language is dynamic
* Language-Learner Language is Systematic