There is a built-in translation system on Mastodon. If it's present on your server, you will see a "Translate" link below posts in other languages. Clicking the link will translate the post.
However, translation systems cost money to run, so not every server has it activated. If you're unsure whether your server has it or not, ask your admin. (You may also consider donating to them to help with their server bills.)
@FediTips I have a public libretranslate server I run if any smaller instances want to use it (just ping me and I’ll provide the info). It’s not perfect, but it’s free and better than nothing at all. 😉
@FediTips if the toot comes from another server, does the option depends on your server being configured for it or the one hosting the toot/account it originated from?
Yeah, unfortunately the feature relies on smaller more open translation services rather than Google etc, so the number of languages supported is smaller.
For privacy/ethical reasons the translation services used tend to be from smaller more open platforms, with fewer resources. Hopefully they improve with time.
@FediTips Does it depend on the detection or whether the person writing in [language] has put that in their settings? I ask because I see the Translate option, but only sometimes, and if it’s on the reader’s instance then the writer’s instance shouldn’t matter, right?
Yes, you need to set your own language in your account settings. It will automatically suggest the "translate" link if the post is written with a different language code.
@FediTips If I’m reading that right that means that multilingual people’s text might not auto-translate, either because they’ve put down nothing in their settings or they haven’t put all of their languages in?