When the learners recognize them, they could correct them. On the other hand, errors are more systematic. When making errors, learners could repeat the same incorrect
forms of language without recognizing the errors. Nevertheless, Brown 1991: 109 proposed a distinct definition of errors. He
classified errors into two types: goofs and mistakes. Goofs are errors made not only by the language learners, but also by the native language users. They are caused by
slips of the tongue and are correctable. Meanwhile, mistakes are errors occurring when the learners attempt to produce the language correctly, as a result of the process
of second language rules system which is incompletely formed. Hence, Brown’s definition of mistakes is similar to the definition of errors defined by Corder.
a. The Sources of Error
Basically, errors are divided into two types. They are interlingual and intralingual errors.
1 Interlingual Errors or Transfer Errors
They are errors which are connected to the first language. In fact, the influence of the first language to the language being learned could be positive or negative. If
the influence does not produce errors, it is called positive transfer. Nevertheless, if it produces errors, it becomes negative transfer or L1 interference Thornbury, 2006:
114. Interlingual errors involve cross-linguistic comparisons. For instance,
sociolinguistic source could influence the errors because “the learners may sometimes deliberately employ non-standard forms of the language as a way of managing the
impression they wish to have on their interlocutor” Rampton 1987 as stated by Ellis and Barkhuizen 2005: 62. Learners do this to show their reluctance to use the
L2 because they do not master it.
2 Intralingual Errors or Developmental Errors
They are errors which are because of the language being learned. Ellis and Barkhuizen 2005: 62 mentioned that psycholinguistic source is a part of this error. It
is related to the processing mechanism involved in the use of the language being learned and to the nature of the language knowledge system
. This type of error is
common to all language learners. Therefore, they become a part of language development Gass and Selinker, 2001: 80. In this case, the learners experience
developmental stages to be nearly the same as the target language. In the developmental stages, learners’ development follows a route, of which the rate is
different for every learner. This development process, then, creates a systematicity. In this stage, learner’s first language and target language are parallel Mitchell and
Myles, 2004: 15-16. Therefore, errors are viewed as “indications of a learner’s attempt to figure out some system; that is, to impose regularity on the language
learner is exposed to do. As such, they are evidence of an underlying rule-governed system” Gass and Selinker, 2001: 78.
Furthermore, as Brown 1991: 111-114 stated, there are four main sources of errors: learners’ native language, the second language itself, the context of the
learning situation, and the strategies employed by the learners.
1 Learners’ Native Language
Learners use their first language as the pattern in learning the new language. The pattern could be in the form of the first language’s sound system, grammatical
system, or vocabulary.
2 The Second Language Itself
Errors are seen as the result of the complexity of the second language. The fact that the second language rule is different from learners’ first language rule makes the
learners confused to produce the second language.
3 The Context of the Learning Situation
Learning situation could become the source of errors. The context of learning language in a classroom which becomes the source of errors are: the teacher’s
limitation in the language mastery, the confusing method in presenting the knowledge, confusing or misleading textbooks, or influence from other students.
4 The Strategies Employed by the Learners
The learners’ strategy in the process of attempting to make the language their own could cause errors. For instance, learners memorize English expressions to apply
them in communication. In fact, those expressions might be inappropriate with the situation of communication.
b. Category of Errors
