Error Analysis and Interlanguage

There have always been two justifications proposed for the study of learners' errors: the pedagogical justification, namely that a good understanding of the nature of error is necessary before a systematic means of eradicating them could be found, and the theoretical justification, which claims that a study of learners' errors is part of the systematic study of the learners' language which is itself necessary to an understanding of the process of second language acquisition. We need to have such a knowledge if we are to make any well-founded proposals for the development and improvement of the materials and techniques of language teaching.