In plain words: They built a system that guesses how good a machine translation is, word by word or for whole sentences and documents, by combining several prediction models with knowledge borrowed from pre-trained language models. Their entries won every track and language pair by a wide margin.
Abstract
We present the contribution of the Unbabel team to the WMT 2019 Shared Task on Quality Estimation. We participated on the word, sentence, and document-level tracks, encompassing 3 language pairs: English-German, English-Russian, and English-French. Our submissions build upon the recent OpenKiwi framework: we combine linear, neural, and predictor-estimator systems with new transfer learning approaches using BERT and XLM pre-trained models. We compare systems individually and propose new ensemble techniques for word and sentence-level predictions. We also propose a simple technique for converting word labels into document-level predictions. Overall, our submitted systems achieve the best results on all tracks and language pairs by a considerable margin.
Fabio Kepler, Jonay Trénous, Marcos Treviso, Miguel Vera, António Góis, M. Amin Farajian, António V. Lopes, André F. T. Martins
arXiv:1907.10352 · cs.CL · submitted Jul 24, 2019 · updated Sep 11, 2019
abstract · pdf · html · In Proceedings of the Fourth Conference on Machine Translation (WMT) 2019: https://www.aclweb.org/anthology/W19-5406/