Errors and Mistakes
Mistakes arise when the speaker fails to match the language to the situation and result in appropriate utterances. Lapses, in the other hand, arise out tiredness, nervousness; or stain which result in slip of tongue, false starts confusion of structure, etc. Both mistake and lapses are not systematical and belong to phenomena of performance.
Unlike the two definitions mentioned above, Dullay in Brown (1987: 170¬) uses the term “errors” to refer to any deviations from a selected norm of language performance, and matter what the characteristics or causes of the definitions might be. They also explain that the norm used to identify the errors may be anyone of the dialect of other varieties of language the native speaker uses.
The terms errors, as noted by Dullay above is used for the systematic deviations due to the learners still developing knowledge of the target language rule, system or for idiosyncrasies in the inter language of the learner which are direct manifestations of system with which a learner is operating at the time.