Study of Individual differences is somewhat marginal in SLA studies, which tend to focus on Universalist aspects of acquisition, it may affect by many factors. Like learning style that refers to the characteristic ways in which individuals orient to problem solving. Foreign language anxiety is also an important part of it. The variable of anxiety has been most studied in SLA in its own right, rather than in connection with personality.
Anxiety is a very important affective factor for the second language learning. Brown (1994) noted that anxiety has been studied in the psychological domain and it is associated with feelings of uneasiness, frustration, self-doubt, apprehension or worry. In Oxford’s opinion, language anxiety is the main factor of those that affect the second language learning (Daimanchun, 2000). In other words, language anxiety refers to the anxiety occurring when a learner is exposed to a foreign language situation. It ranks high among factors influencing second language acquisition, regardless of whether the setting is informal (learning language outside the classroom) or formal (inside the language classroom).
The main source of anxiety are :personal and interpersonal anxieties; learner beliefs about language learning; instructor beliefs about language teaching; instructor-learner interactions; classroom procedures; language testing. Factors correlated with language anxiety are Self-esteem, Unsuccessful language learners often have lower self-esteem than successful language learners .Another one is belief, Influenced by previous experiences as language learners, or shaped by their own cultural backgrounds, second language learners often hold different beliefs or notions about language learning, Belief is one of the characteristics the learners hold about in the process of language learning.
The best known measure of anxiety is the Foreign Language Classroom Anxiety Scale (FLCAS), developed by Horwitz and colleagues (Horwitz et al.