The document discusses error analysis in second language acquisition. It begins by stating that making errors is natural and inevitable in language learning. It then defines error analysis as the systematic study of deviations from target language norms during second language acquisition. The history of error analysis is discussed, noting that it was established in the 1960s as an alternative to contrastive analysis. Error analysis showed that contrastive analysis could not predict most learner errors. The document also discusses different ways of classifying errors and some methodological problems with error analysis approaches. It concludes by distinguishing between errors, mistakes, and lapses in learner language.