Not All Contexts are Important: The Impact of Effective Context in Conversational Neural Machine Translation

Multilingual chat systems are the need of the hour for organizations who render online conversational services to their customers. This can effectively be facilitated using the robust machine translation (MT) systems. Translating user-generated contents is regarded as one of the challenging tasks for MT. As for translating conversations, it is more challenging since the meaning of any particular utterance in a conversation usually depends on its context. Moreover, chats in conversational systems are usually informal, contain code-mixed (mix of more than one language), and other grammatical inconsistencies. In this paper, we use state-of-the-art Transformer models to build our MT systems and to translate conversations between the customer service agents and customers. We propose a novel method which effectively selects contextual information from the source text of conversation to be translated. We also employ a terminology-based pseudo in-domain corpus mining strategy for fine-tuning our translation model. We evaluate our methods on the German–English WMT20 Shared Task on Chat Translation dataset, and obtain 61.1 and 63.9 BLEU points on evaluation test sets for English-to-German and German-to-English, respectively, surpassing the present state-of-the-art MT systems by 0.7 BLEU and 1.5 BLEU points, respectively