Shuichiro Shimizu


2023

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Video-Helpful Multimodal Machine Translation
Yihang Li | Shuichiro Shimizu | Chenhui Chu | Sadao Kurohashi | Wei Li
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

Existing multimodal machine translation (MMT) datasets consist of images and video captions or instructional video subtitles, which rarely contain linguistic ambiguity, making visual information ineffective in generating appropriate translations. Recent work has constructed an ambiguous subtitles dataset to alleviate this problem but is still limited to the problem that videos do not necessarily contribute to disambiguation. We introduce EVA (Extensive training set and Video-helpful evaluation set for Ambiguous subtitles translation), an MMT dataset containing 852k Japanese-English parallel subtitle pairs, 520k Chinese-English parallel subtitle pairs, and corresponding video clips collected from movies and TV episodes. In addition to the extensive training set, EVA contains a video-helpful evaluation set in which subtitles are ambiguous, and videos are guaranteed helpful for disambiguation. Furthermore, we propose SAFA, an MMT model based on the Selective Attention model with two novel methods: Frame attention loss and Ambiguity augmentation, aiming to use videos in EVA for disambiguation fully. Experiments on EVA show that visual information and the proposed methods can boost translation performance, and our model performs significantly better than existing MMT models.

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The Kyoto Speech-to-Speech Translation System for IWSLT 2023
Zhengdong Yang | Shuichiro Shimizu | Wangjin Zhou | Sheng Li | Chenhui Chu
Proceedings of the 20th International Conference on Spoken Language Translation (IWSLT 2023)

This paper describes the Kyoto speech-to-speech translation system for IWSLT 2023. Our system is a combination of speech-to-text translation and text-to-speech synthesis. For the speech-to-text translation model, we used the dual-decoderTransformer model. For text-to-speech synthesis model, we took a cascade approach of an acoustic model and a vocoder.

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Towards Speech Dialogue Translation Mediating Speakers of Different Languages
Shuichiro Shimizu | Chenhui Chu | Sheng Li | Sadao Kurohashi
Findings of the Association for Computational Linguistics: ACL 2023

We present a new task, speech dialogue translation mediating speakers of different languages. We construct the SpeechBSD dataset for the task and conduct baseline experiments. Furthermore, we consider context to be an important aspect that needs to be addressed in this task and propose two ways of utilizing context, namely monolingual context and bilingual context. We conduct cascaded speech translation experiments using Whisper and mBART, and show that bilingual context performs better in our settings.

2022

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VISA: An Ambiguous Subtitles Dataset for Visual Scene-aware Machine Translation
Yihang Li | Shuichiro Shimizu | Weiqi Gu | Chenhui Chu | Sadao Kurohashi
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Existing multimodal machine translation (MMT) datasets consist of images and video captions or general subtitles which rarely contain linguistic ambiguity, making visual information not so effective to generate appropriate translations. We introduce VISA, a new dataset that consists of 40k Japanese-English parallel sentence pairs and corresponding video clips with the following key features: (1) the parallel sentences are subtitles from movies and TV episodes; (2) the source subtitles are ambiguous, which means they have multiple possible translations with different meanings; (3) we divide the dataset into Polysemy and Omission according to the cause of ambiguity. We show that VISA is challenging for the latest MMT system, and we hope that the dataset can facilitate MMT research.

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Filtering of Noisy Web-Crawled Parallel Corpus: the Japanese-Bulgarian Language Pair
Iglika Nikolova-Stoupak | Shuichiro Shimizu | Chenhui Chu | Sadao Kurohashi
Proceedings of the 5th International Conference on Computational Linguistics in Bulgaria (CLIB 2022)

One of the main challenges within the rapidly developing field of neural machine translation is its application to low-resource languages. Recent attempts to provide large parallel corpora in rare language pairs include the generation of web-crawled corpora, which may be vast but are, unfortunately, excessively noisy. The corpus utilised to train machine translation models in the study is CCMatrix, provided by OPUS. Firstly, the corpus is cleaned based on a number of heuristic rules. Then, parts of it are selected in three discrete ways: at random, based on the “margin distance” metric that is native to the CCMatrix dataset, and based on scores derived through the application of a state-of-the-art classifier model (Acarcicek et al., 2020) utilised in a thematic WMT shared task. The performance of the issuing models is evaluated and compared. The classifier-based model does not reach high performance as compared with its margin-based counterpart, opening a discussion of ways for further improvement. Still, BLEU scores surpass those of Acarcicek et al.’s (2020) paper by over 15 points.