10 Error Analysis and Intel-language
study of learners' errors would assume the role it already plays in the study of child language acquisition, since, as has been pointed out, the key concept in both cases is that the learner is using a definite system of language at every point in his development, although it is not the adult system in the one case, nor that of the second language in the other. The learner's errors are evidence of this system and are themselves systematic.
The use of the term systematic in this context implies, of course, that there may be errors which are random, or, more properly, the systematic nature of which cannot be readily • discerned. The opposition between systematic and non-systematic errors is important. We are all aware that in normal adult speech in our native language we are continually committing errors of one sort or another. These, as we have been so often reminded recently, are due to memory lapses, physical states such as tiredness, and psycho¬logical conditions such as strong emotion. These are adventitious artefacts of linguistic performance and do not reflect a defect in our knowledge of our own language. We are normally immediately aware of them when they occur and can correct them with more or less complete assurance. It would be quite unreasonable to expect the learner of a second language not to exhibit such slips of the tongue (or pen), since he is subject to similar external and internal conditions when performing in his first or second language. We must therefore make a distinction between those errors which are the product of such chance circumstances and those which reveal his underlying knowledge of the language to date, or, as we may call it his transitional competence. The errors of performance will characteristically be unsystematic and the errors of competence, systematic. As Miller (1966) puts it, 'It would be meaningless to state rules for making mistakes'. It will be useful therefore hereafter to refer to errors of performance as mistakes, reserving the term error to refer to the systematic errors of the learner from which we are able to reconstruct his knowledge of the language to date, i.e. his transitional competence.
Mistakes are of no significance to the process of language learning. However, the problem of determining what is a learner's mistake and what a learner's error is one of some difficulty and involves a much more sophisticated study and analysis of errors than is usually accorded them.
A learner's errors, then, provide evidence of the system of the language that he is using (i.e. has learnt) at a particular point in the course (and it must be repeated that he is using some system, although it is not yet the right system). They are significant in three different ways. First to the teacher, in that they tell him, if he