Interlanguage

Interlanguage is the type of language produced by second and foreign language learners who are in the process of learning a language. In language learning, learner’s errors are caused by several different processes. These include: a. borrowing patterns from the mother tongue b. extending patterns from the target language. c. Expressing meanings using the words and grammar which are already known.
Teachers can give appropriate feedback after checking out learner’s interlanguage. Learners need not worry so much about making mistakes. They can assume that making mistakes is a procedure of development from mother tongue to Second Language.

Reference:

• http://duermueller.tripod.com/interlanguage.html