Speech interaction is a prominent interaction technology in educational robot, and educational robot with speech interaction can have a more harmonic and natural way of interaction. In some specific application scenarios such as education, the performance of speech recognition is not satisfactory due to the wide range of vocabularies and poor network. This paper trains the language model with professional vocabulary in the specific subject and establishes the corresponding phonetic dictionary in speech recognition based on Sphinx, and combines with speech synthesis based on Ekho to implement t...