Errors of a language learner

Errors may occur in the speech writing of a second or foreign language learner. An error is the use of a linguistic item in a way which from the viewpoint of a native speaker, is regarded as faulty or as the result of incompetent learning. Errors have been classified into various types. When an error results from incomplete knowledge it is called an error .When it is made by a learner due to fatigue carelessness, or lack of attention ,it is called a lexical error ,when it is pronunciation it is called a phonological error and when it occurs due to lack of grammatical knowledge, it is a syntactic error is called a global error.An error in the use of a first or second language learner may be the result of a normal pattern of development. Such an error is called the developmental error .So errors of a language learner may be of different classes