خلاصه ماشینی:
"In fact, most first and second language reading researchers consider vocabulary knowledge an important variable that affects reading comprehension (Nation & Coady, 1988; Laufer, 1992).
Vocabulary Density and Coverage Several studies have attempted to determine the amount of vocabulary needed by a second language learner in order to be able to read with reasonable comprehension and without lack of vocabulary knowledge becoming a major burden (Hirsh & Nation, 1992; Laufer, 1989, 1992).
Language Threshold The features discussed about coverage have led several researchers to consider that there may be a threshold where vocabulary knowledge becomes sufficient for adequate comprehension (Read, 1988; Laufer & Nation, 1999).
For this purpose, the following research questions and corresponding null hypotheses were formed: Q1: Do different densities of unknown academic vocabulary result in significant differences in EFL learners’ comprehension of nonfiction general English texts?
Results In this study, the performance of the subjects on different versions of the same reading comprehension test was the dependant variable and the unknown vocabulary size was the independent variable.
Therefore, the present study attempted to examine the effect of different densities of unknown vocabulary size on the reading comprehension performance of Iranian EFL learners.
Results of the present study indicated that the subjects’ performance on reading comprehension tests and subsequently, their text comprehensions was highly sensitive to densities of unknown vocabulary size in nonfiction general English texts with academic words as a point of departure."