The role of music in second-language (L2) learning has long been the object of various empirical and theoretical inquiries. However, research on whether the effect of background music (BM) on language-related task performance is facilitative or inhibitory has produced inconsistent findings. Hence, we investigated the effect of happy and sad BM on complexity, accuracy, and fluency (CAF) of L2 speaking among intermediate learners of English. A between-groups design was used, in which 60 participants were randomly assigned to three groups with two experimental groups performing an oral L2 English retelling task while listening to either happy or sad BM, and a control group performing the task with no background music. The results demonstrated the happy BM group’s significant outperformance in fluency over the control group. In accuracy, the happy BM group also outdid the controls (error-free clauses, correct verb forms). Moreover, the sad BM group performed better in accuracy than the controls but in only one of its measures (correct verb forms). Furthermore, no significant difference between the groups in syntactic complexity was observed. The study, in line with the current literature on BM effects, suggests that it might have specific impacts on L2 oral production, explained by factors such as mood, arousal, neural mechanism, and the target task’s properties.

音乐在第二语言 (L2) 学习中的作用长期以来一直是各种经验和理论研究的对象。然而，关于背景音乐 (BM) 对语言相关任务表现的影响是促进性还是抑制性的研究产生了不一致的发现。因此，我们研究了快乐和悲伤 BM 对中级英语学习者 L2 口语的复杂性、准确性和流畅性 (CAF) 的影响。使用组间设计，其中 60 名参与者被随机分配到三组，两个实验组在听快乐或悲伤的 BM 的同时执行口语 L2 英语复述任务，以及在没有背景音乐的情况下执行任务的对照组。结果表明，快乐 BM 组在流畅度方面的表现明显优于对照组。在准确度上，快乐 BM 组也超越了控制（无错误从句，正确的动词形式）。此外，悲伤的 BM 组在准确性上比对照组表现更好，但仅在其一项措施（正确的动词形式）方面表现得更好。此外，在句法复杂性方面没有观察到组之间的显着差异。该研究与当前关于 BM 效应的文献一致，表明它可能对 L2 口语产生有特定影响，这可以通过情绪、唤醒、神经机制和目标任务的属性等因素来解释。