For which languages pairs does Amazon Translate support *customisation*?

[bittlingmayer]

Does Amazon Translate support "customisation with parallel with data" for all the languages it supports, including non-English language pairs?

There are no limitations mentioned at:

• https://docs.aws.amazon.com/translate/latest/dg/customizing-translations-parallel-data.html
• https://docs.aws.amazon.com/translate/latest/dg/what-is-languages.html#what-is-languages-by-feature

This would make sense, because its customisation approach is copied from ModernMT, and ModernMT works for non-English language pairs?

But I just want to be sure, since customisation support for non-English pairs is relatively rare.

And we should be clear about https://github.com/machinetranslate/machinetranslate.org/blob/master/_data/engines.yml

If custom_languages is not included, it means that customisation is supported for language pairs for which translation is supported?