Abstract
This study intended to investigate the relationship between the number of correct lexical collocations and expressiveness in a writing task. 45 Iranian undergraduate EFL learners of an English language institute in Tehran who had passed the upper-intermediate level were recruited to sit for a model test of IELTS writing task 1 to describe a single-line graph. Before the test, they had undergone a 50-hour course of instructions on how to accomplish the IELTS writing task 1 focusing on the correct and effective use of suitable collocations. The number of correct collocations of each participant in the test was extracted. An experienced IELTS teacher and assessor was asked to rate the expressiveness of each writing on the scale of 1 to 10. Expressiveness in this study implies the extent to which each participant was able to convey the single-line graph to the assessor who had not seen the graph before rating the EFL learners' written description of the graph. Since the participants try to convey information of a graph and a context is oriented, the referential function of language is involved and is tried to be fulfilled by the participants. Spearman rank correlation was conducted to investigate the relationship between the number of correct lexical collocations and expressiveness. The results (rs = 0.886, N = 45, p< 0.01) showed a strong and significant relation.