IntroductionThe study of the mental lexicon deals with how words are acquired, understood, organised, stored, retrieved and produced. The term “mental lexicon” is used interchangeably with what some scholars call “internal lexicon” (Bonin, 2004). It involves the different processes and activations carried out in the brain to store words and form an internal memory that works like a mental dictionary. The psychologists and linguists involved in this study believe that words are stored in relation to their phonological, semantic, syntactic and even orthographic characteristics. The first studies in this field were started at the end of the 1960s. The main focus of the studies was word comprehension and production. Most of the studies were psychologically oriented. The introduction of this concept into linguistics has shifted attention to phonological, semantic and syntactic representations in the mind. Aitchison (1994) described the mental lexicon as the permanent human dictionary in which words and their meanings are stored in the brain. On the other hand, Richards (2000) described the mental lexicon as the organized mental representations of concepts and knowledge related to words. There are three areas of knowledge of words; phonological, morphological, syntactic and semantic.I. Phonological knowledge Attention to phonological mental memory was first initiated by Paul Meara (1980). He argued that the organization of words in memory depends on the phonological knowledge of words in second language acquisition. However, in first language acquisition, memory depends on semantic knowledge. Mear (1980) conducted a study on lexical performance in fir...... middle of paper ...... 15-31.Prarthana,S. & Prema, K. (2012). Role of semantics in the organization of the mental lexicon. Language in India.259-277.Richards, J.C., Platt, J., & Plat, H. (2000). Longman Dictionary of Language Teaching and Applied Linguistics. Beijing: Foreign Language Teaching and Research Press.Roux, p. (2013). Words in the mind: Exploring the relationship between word association and lexical development. Journal of Polyglossia, pp. 80-91. Singleton, D. (1999). Exploring the mental lexicon of the second language (p. 178, 236). London: Cambridge University Press.Wolter. B. (2001). Comparison between the mental lexicon of L1 and L2. Studies on second language acquisition. 23:41-69.Zhang, C. (2009). Mental lexicon and English vocabulary teaching. US-China Foreign Language, 3-7.Zhang, S. (2004). The mental lexicon of CLE: nature and model of development. Kaifeng: Henan Press.