Section 3.3 of the paper[0] covers this. 93% of the training data was English, and the rest other languages. (German, French and a long tail of other languages.) This was not training data specifically for translation, but a natural mix of language as it appears in some documents.
With a few prompts to explain the translation task, GPT-3 is claimed to perform well on certain translation tasks to English. (It was not as good as the state of the art in the other direction.)
With a few prompts to explain the translation task, GPT-3 is claimed to perform well on certain translation tasks to English. (It was not as good as the state of the art in the other direction.)
[0] https://arxiv.org/abs/2005.14165