The present study explored how negotiation of meaning occurred in task-based synchronous computer-mediated communication (SCMC) environment among college English learners. Based on the theoretical framework of the interaction hypothesis and negotiation of meaning, four research questions arose: (1) how negotiation of meaning occur in non-native to non-native interactions in CMC, (2) whether learners' proficiency levels have an effect on non-native to non-native interactional modifications during the completion of the tasks, (3) how task types affect the negotiation of meaning in terms of quantity and quality, (4) what learner perceptions of tasks and CMC are displayed. Thirty two ESL students (14 beginning and 18 advanced-level students) at the University of Texas at Austin participated in this study. Paired with one another, they were asked to engage 50 to 60 minute-long online conversations once a week for three weeks via MSN Messenger in order to complete three types of language task: (1) jigsaw, (2) information-gap, (3) decision-making tasks. In order to answer each research question, data analysis was based on the following theoretical, statistical and qualitative methodology: (1) Long's classification and Varonis & Gass' (1985) model, (2) multivariate analysis of variance (MANOVA), (3) t-test and paired sample test, (4) interviews. In assessing the number of negotiation of meaning, the data revealed that only a few examples (11%, 534/4970 c-units) contributed to negotiation routines. Twenty-two % of the negotiation routines were identified as modified interactions. Proficiency levels did not have a significant effect on the production of the negotiation routines (10% for the beginners vs. 11% for the advanced level students). However, task types were an influential factor in generating negotiation routines. Jigsaw-type task elicited the most negotiation routines for the beginning-level students whereas information-gap did for the advanced. Although the quantitative data revealed that the jigsaw was the most negotiation-eliciting task for the beginning-level students and the information-gap the most for the advanced, the students perceived the task types differently. Although the beginning-level students showing consistency in their quantitative results and their perception of the tasks, the advanced students displayed a disparity between the numerical results and their perceived understanding of task types. The advanced students perceived the jigsaw as the most useful task in improving their proficiency. This can be attributed to a personality trait of not asking questions or their eagerness to proceed with the task. In addition, culturally-appropriate efforts aimed at maintaining social relationships among these advanced students were uncovered. Relying on guessing or imagination instead of asking for clarification and feigning a faulty sign of understanding were observed as efforts to maintain social communication through a pretending to comprehend. This study to investigate NNS/NNS interactions in task-based SCMC gave researchers and teachers a window to better understand the reality of online discussion where students produced negotiation of meaning as incomplete understanding occurred. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]