Language teaching is a field in constant evolution and the use of technology has boosted its development. This article explores the design and the implementation of synchronous and asynchronous learning activities to develop oral skills in an online English course. The article uses a mix-methods approach that combines qualitative and quantitative research methods. The participants in the study were 6 graduate students. The main findings of this investigation show that the synchronous learning activities prompt errors that translate into opportunities for learning. These results show that the use of asynchronous learning activities produce errors despite the fact that the participants have time to prepare and anticipate language inaccuracies. The results suggest that the use of asynchronous learning activities promotes the development of language awareness as participants can identify general categories of errors.