Development of EFL University Students’ Vocabulary Size and Reading Comprehension Using Online Multimedia-based Extensive Reading
Authors: Chavangklang Thanaset , Chavangklang Pitchayapa , Thiamhuanok Sirichai , Sathitdetkunchorn Premkamon 
Published: March 2020

The objectives of this study were: 1) to investigate the effects of online multimedia-based extensive reading activities on students’ vocabulary size; 2) to investigate the effect of online multimedia-based extensive reading activities on students’ reading comprehension, and 3) to investigate the relationship between vocabulary size and reading comprehension. The population of the study was EFL students at Nakhon Ratchasima Rajabhat University enrolling in the Reading Comprehension course, and the samples were 67 students from two classes who enrolled in the course in semester 1 of the academic year 2018. The classes were randomly assigned an experimental group and the other the controlled group. The study tools included pretest and posttest and the online multimedia-based extensive reading activities. The two groups undertook the same course instructions; however, the experimental group was assigned to do extensive reading activities, which included reading three different online news articles each week. Both groups took pretest and posttest for vocabulary size and reading comprehension. The results of the study can be summarized as follows. 1. The two groups had their posttest scores significantly higher than the pretest scores on both the vocabulary size and reading comprehension at the.05 level. However, comparisons between the scores of the two groups revealed no differences, neither on the pretest nor the posttest. 2. No differences were found between the pretest and the posttest scores on reading comprehension of the control group. However, the posttest scores on reading comprehension of the experimental group were significantly higher than those of the pretest at the.01 level. Additionally, the experimental group had significantly higher posttest scores than the control group at the.01 level. 3. The regression analysis revealed the coefficients of 20.981, t-Stat of 7.604 with the p-value = 0.000. This means that the vocabulary size factor can be a predictor of the reading comprehension factor at the 95% confidence level.The findings of this study suggest that online multimedia-based extensive reading activities can significantly improve both students’ vocabulary size and reading comprehension. Moreover, vocabulary size also found to be a good predictor of reading comprehension. It can be concluded from the findings that the improved vocabulary size and reading comprehension were largely due to the effect of the online multimedia-based extensive reading activities which helped expand vocabulary size. More importantly, the activities supported students’ reading in terms of translation, anywhere and anytime reading, as well as ways to find more vocabulary online, etc. This type of extensive reading is regarded as an effective method for improving students’ reading comprehension through the expansion of their vocabulary size, which has to be considered not only at the classroom level by the instructors, but also at the course and curriculum levels by the course and curriculum designers or developers.