Learning English articles and demonstratives by EFL learners of articleless first languages has attracted considerable attention. However, learning them by Persian speaking English learners has not attracted the attention as it deserves. To bridge this gap, the present research investigates whether Iranian EFL learners can distinguish the English contexts in which merely a definite article or a demonstrative description can be used from the contexts that are amenable to both definite and demonstrative descriptions. It also examins whether Iranian EFL learners’ perception and production of English demonstrative are influenced by their proficiency level. To do so, 75 Iranian EFL learners with different levels of proficiency were selected to complete comprehension and production tasks. The production task investigated the participants’ use of definite and demonstrative descriptions across the three contexts of ‘’unique and salient”, “unique and nonsalient” and “nonunique”. The comprehension task scrutinized the participants’ perception of definite plurals, indefinite plurals, and demonstrative plurals. The participants’ performance of the tasks was compared with English native speakers’ performance on the same tasks. The results revealed that the participants could learn both definite and demonstrative descriptions; however, their performance in the use of demonstratives proved to be more target-like compared to their performance on definite descriptions. The results were also indicative of the participants’ inconsistency in using the article and demonstrative descriptions (e.g. using both the and that in contexts merely allowing the or that). Finally, the results demonstrated that the effect of the participants’ level of proficiency on their performance was governed by task type, proficiency affected learners’ comprehension, and production of definite articles and determiners differently. These findings suggest that EFL instruction should emphasize the subtle distinctions between definite articles and demonstratives through targeted practice, explicit instruction, and contextualized learning activities to enhance learners’ accuracy and naturalness in article use.
