In the process of learning a second language, modern Chinese learners are faced with many challenges due to the limitations of the learning environment and teaching conditions. The teachers are usually non-native speakers, and their language level is uneven, resulting in unsatisfactory teaching results. At the same time, the size of the group learning a second language continues to expand, and the requirement for teaching level is getting higher and higher. The topic of this paper is the application of deep learning to speech recognition and language teaching. The results and effects of deep learning in speech recognition and language teaching are summarized by combining the currently available information. It can be found that the current deep learning technology is more and more advanced, the accuracy rate of speech recognition technology has been greatly improved compared with the past, and the teaching effect has also made no small achievements. This technology can not only help learners better master English pronunciation, but also provide more efficient and effective learning experience.