With the increasing popularity of online language exchange platforms, understanding the motivational dynamics that drive learners' engagement and persistence in these informal learning environments is crucial. This study explores how the satisfaction of basic psychological needs—autonomy, competence, and relatedness—impacts the motivation of Chinese learners of English participating in online language exchange platforms, specifically Tandem and HelloTalk. Grounded in Self-Determination Theory (SDT), the research employed a quantitative design involving 120 Chinese learners of English. Participants completed measures assessing motivation, psychological needs satisfaction, and engagement with the platforms. Data analysis, including descriptive statistics, correlation analysis, multiple regression, and moderation analysis, revealed that autonomy and competence were the strongest predictors of intrinsic motivation, while relatedness had a more significant impact on extrinsic motivation. Amotivation was negatively correlated with autonomy and competence, highlighting the importance of satisfying these needs to prevent disengagement. Additionally, platform usage frequency moderated the relationship between autonomy and intrinsic motivation, amplifying its effects with increased usage. These findings underscore the critical role of basic psychological needs in shaping motivation in informal, peer-to-peer language learning contexts. The study suggests that online language exchange platforms can be optimized by incorporating features that support learners' needs for autonomy, competence, and relatedness, such as personalized learning paths, opportunities for social interaction, and effective feedback mechanisms. These findings offer valuable insights for educators and platform designers seeking to enhance learner motivation and promote successful language learning experiences in online environments.
