We present a simple approach to improve direct speech-to-text translation (ST) when the source language is low-resource: we pre-train the model on a high-resource automatic speech recognition (ASR) task, and then fine-tune its parameters for ST. We demonstrate that our approach is effective by pre-training on 300 hours of English ASR data to improve Spanish-English ST from 10.8 to 20.2 BLEU when only 20 hours of Spanish-English ST training data is available. Through an ablation study, we find that the pre-trained encoder (acoustic model) accounts for most of the improvement, which is surprising since the shared language in these tasks is the target language (text), and not the source language (audio). Applying this insight, we show that pre-training on ASR helps ST even when the ASR language differs from both source and target ST languages: pre-training on French ASR also improves Spanish-English ST. Finally, we show that the approach improves a true low-resource task: pre-training on a combination of English ASR and French ASR improves Mboshi-French ST, where only 4 hours of data are available, from 3.5 to 7.1 BLEU.

本文研究通过使用大量训练数据的自动语音识别任务，对语音翻译进行预训练，以提高低资源环境下的语音翻译性能，其中预训练的声学模型起到了关键的作用，并且可用于不同语言对之间的翻译。经验证本方法效果显著，能够在真实的低资源任务中提高性能。

高资源语音识别预训练改进低资源语音到文本翻译