Research on Machine Translation Automatic Evaluation Based on Extended Reference

Language is the main carrier of communication between cultures, but the translation between languages has become the biggest problem of people's communication. Machine translation is a process that uses computer to transform a natural language into another natural language. The automatic evaluation of machine translation is an important research content in machine translation technology. It can discover defects in translation system and promote its development. It has achieved rich fruits, and various evaluation methods emerge endlessly after several decades of development of the automatic evaluation method. In this paper, three kinds of representative evaluation methods are introduced and their respective advantages and disadvantages are analyzed. In addition, we describe the evaluation technique based on reference. It plays an important role in improving the performance of automatic evaluation methods although the coverage expansion of reference is not the main method. Finally, we summarize the development trends of automatic evaluation metric based on extended reference and related issues that need to be further addressed.