Apertium, a free open alternative to Google Translate, is currently under development (https://apertium.org).
However, there is some disagreement in the development about whether to use certain third party services which may affect privacy:
I'm not a developer, so I don't know what the technical trade-offs are here with viability vs privacy.
However, if you are a developer interested in the project, please do make your opinion known in the thread above.
@switchingsocial first tell them to avoid GitHub. It's not privacy-friendly.
It does seem to be a popular alternative.
However, it is important to also emphasise that the free-of-charge version of DeepL is not private. (The DeepL site explicitly says you have to pay for privacy.)
@switchingsocial 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏 👏
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