Recent research shows that bi-lingual competence is one of the necessary skills that a translator needs in order to translate (PACTE, 2003). Apart from the mother tongue, a translator must have a command of other working languages. The purpose of this study was to investigate whether the online multimedia-supported learning environment concerning collocations in English (OMLEC) was effective in helping learners develop their bilingual skills through the acquisition of collocations. As a method, a quasi-experimental design was used. The study consisted of 40 students, 20 of whom were undergraduate ELT students and the other 20 were preparatory ELT students. The participants took a variety of tests such as diagnostic, study, achievement, and summative tests. A repeated measure ANOVA analysis was used to analyze the results of the tests. The results indicate that the OMLEC platform has made a significant contribution to learners' knowledge of bi-lingual competence through collocations. There was a significant difference between the diagnostic and study test scores, the diagnostic and achievement test scores, the diagnostic and summative test scores, the study and achievement test scores, and the study and summative test scores.