A Study on the Way in which Words Are Organized in Iranian EFL Learners’ Mental Lexicon Sedigheh Sharif 1 , Masoud Khalili Sabet 2 , Abdorreza Tahriri 2 1 English Department, the University of Guilan, Rasht, Guilan, Iran 2 Faculty member at the University of Guilan, Rasht, Guilan, Iran Corresponding Author: Sedigheh Sharif, E-mail: sedighehsharif19@gmail.com ABSTRACT Vocabulary learning in both L1 and L2 is considered important to master a language. Individuals need to learn the words in order to express ideas and to communicate. As a result, research into word knowledge is important as it provides useful information considering the way in which words are learned and organized in individuals’ mind; however different studies have been conducted in this regard, there is a long way to fully understand individuals’ mental lexicon. So, word association tests are used to examine the word knowledge, to study vocabulary learning process, and how it occurs in the language learners’ mind. Similarly, the aim of this paper is to investigate the way in which words are stored and organized in Iranian EFL learners’ mental lexicon through a word association test. To this end, a word association test was designed including eight prompt words from different word classes and was administered to 50 Iranian EFL learners. They were randomly selected and included 22 males and 28 females from Razi University and an institute in Kermanshah, Iran. After administering the test, to analyze the data, learners’ responses were classifed and the frequency of each classifcation of word association was calculated and chi-square tests were run to compare responses. Results reveal that the participants displayed different patterns in their responses as syntagmatic and paradigmatic classifcation. Most of them made more syntagmatic responses than paradigmatic ones. As a result, it can be concluded that more participants make mental links with syntagmatic compared to others who make links with paradigmatic and there are signifcant differences between male and female learners in the use of syntagmatic and paradigmatic responses; on the other hand, it appears that there is no signifcant differences in learners’ word association regarding age. This study has useful implications for both EFL teachers and learners by helping them understand and improve the lexical acquisition process. Key words: Word Association, Mental Lexicon, Syntagmatic and Paradigmatic Links INTRODUCTION The present study is going to provide precise insight into the way in which words are learned, organized, and linked in the EFL learners’ mind by using a perfect word association test. Therefore, this paper will uncover the organization and development of words in learners’ mental lexicon. The process of foreign language learning refers to the learning a nonnative language that is not the language of communication of the environment in which the language is learned (Moeller & Catalano, 2015). Primarily, vocabulary is regarded as a basic aspect in language learning process. That is why vocabulary is now occupied a center stage in all language learning programs. So, it is understood that vo- cabulary knowledge is very essential for learners’ academic attainments. (Udaya, 2015, p.43) Nation (1990) lists a number of various types of word knowledge that every single individual requires to have so that (s) he knows a word, such knowledge as pronunciation, Published by Australian International Academic Centre PTY.LTD. Copyright (c) the author(s). This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) http://dx.doi.org/10.7575/aiac.ijalel.v.7n.6p.80 spelling, grammatical class, collocation, register, frequency, and association of word. These are referred to as kinds of word knowledge, and they are required to make possible to know a word and to use it in different language situations individuals put in. (cited in Schmitt, 2000). Every knowledge regarding vocabulary has a well orga- nization in one’s mind such as the way in which words are stored and interrelated to one another in the mental lexicon (Fidayanti, 2013). Schmitt (2014) believes that: “The mental lexicon is a complex phenomenon, and the exact nature of lexical knowledge has always perplexed re- searchers and teachers. This is not surprising as a lexicon can hold many thousands of words, each with numerous links of various kinds to the other words in the lexical network. Moreover, the links between different words are often diff- cult to explain clearly, thus making research into these links diffcult. Descriptions of the mental lexicon are further com- plicated by the fact that each word does not usually exist on International Journal of Applied Linguistics & English Literature E-ISSN: 2200-3452 & P-ISSN: 2200-3592 www.ijalel.aiac.org.au ARTICLE INFO Article history Received: April 22, 2018 Accepted: July 29, 2018 Published: November 01, 2018 Volume: 7 Issue: 6 Advance access: September 2018 Conficts of interest: None Funding: None