lel I worked on a couple speech interface projects back in the 00s before all these corporate spyware platforms emerged. Naturally, it was all on-device (or a local server we controlled). This was more R&D/prototype stuff so it wasn't as robust as systems nowadays, but the software is still out there:
- Speech Recognition: https://cmusphinx.github.io/
- we weren't doing translation so idk about that
- Text-To-Speech: https://github.com/festvox/festival