Resumen:
Studies on second language acquisition have examined the effectiveness of different types of feedback on improving skills when learning an L2. Findings have shown a positive impact of direct and indirect types of feedback on learners’ written and oral production, that is why conducting research on this topic has become more necessary so that a wider amount of information could be provided to learners and instructors to reach more accurate results in their teaching and learning processes. The objective of this study is to measure the impact of two types of delayed explicit feedback, explicit correction and metalinguistic feedback, on the pronunciation of English vowels by Chilean learners in an online instructional setting. The study was conducted in Chile during six weeks. 56 university students participated in the research. Participants were separated in three groups (CG: Control Group; EG1: Experimental Group 1; EG2: Experimental Group 2). By the end of the investigation, the two experimental groups improved their pronunciation of English vowels, being metalinguistic feedback group the one that showed greater improvement in comparison to the explicit correction group.