Machine Translation Evaluation: Unveiling the Role of Dense Sentence Vector Embedding for Morphologically Rich Language

Machine Translation (MT) evaluation metrics like BiLingual Evaluation Understudy (BLEU) and Metric for Evaluation of Translation with Explicit Ordering (METEOR) are known to have poor performance for word-order and morphologically rich languages. Application of linguistic knowledge to evaluate MTs for morphologically rich language like Hindi as a target language, is shown to be more effective and accurate [S. Tripathi and V. Kansal, Using linguistic knowledge for machine translation evaluation with Hindi as a target language, Comput. Sist. 21(4) (2017) 717-724]. Leveraging the recent progress made in the domain of word vector and sentence vector embedding [T. Mikolov and J. Dean, Distributed representations of words and phrases and their compositionality, Adv. Neural Inf. Process. Syst. 2 (2013) 3111-3119], authors have trained a large corpus of pre-processed Hindi text (similar to 112 million tokens) for obtaining the word vectors and sentence vector embedding for Hindi. The training has been performed on high end system configuration utilizing Google Cloud platform resources. This sentence vector embedding is further used to corroborate the findings through linguistic knowledge in evaluation metric. For morphologically rich language as target, evaluation metric of MT systems is considered as an optimal solution. In this paper, authors have demonstrated that MT evaluation using sentence embedding-based approach closely mirrors linguistic evaluation technique. The relevant codes used to generate the vector embedding for Hindi have been uploaded on code sharing platform Github.(a)