Fossilization has become the focus of many L2 studies since its introduction in 1972 as many learners fail to achieve native-speaker competence. Researchers have tried to unravel the causes of fossilization, among which noticing has been claimed to be of great importance. This study aimed to explore the effect of noticing on fossilization. To achieve this aim, a mixed methods approach was utilized. Sixty advanced L1 Persian learners of English studying in Iran were chosen to perform two written and three spoken tasks twice. Qualitative data included the content analysis of the participants’ performance on the written and spoken tasks while the quantitative data included percentages of noticed errors and recurrent erroneous forms. The errors observed in both performances were counted and classified. Six main categories named Grammatical Errors, Lexical Errors, and Cohesive Errors were identified. The observed errors were further classified into 61 subcategories. When learners’ ability in noticing their errors was investigated, it was found that they could notice 37.4% of the 3,796 fossilized forms they had produced. Most of the errors observed were categorized in the category of grammatical errors. Noticing affected the number of errors produced. It can be concluded that becoming aware of ones fossilized forms, one will produce fewer fossilized forms. The results of the current study have implications for English language teachers and learners. By being informed of the errors learners make while learning a language and how their noticing affects fossilization, teachers can improve their teaching practice which in turn enhances learning.
