Someone shared Chinese in this post, you need to copy it to a file.
See this post on Korean, it was installable as language file it seems in the past
Hi, I’m from Greece and I bought garmin vivoactive 3 from a Greek site .. I think it’s apac version because I only see few languages like Taiwan..I didn’t knew about versions and it’s not fair..there is not Greek menu.... what can i do now .. how can I download my language?.. at garmin express says there is not any languages to update.. can anyone help me?
I have just found a smart way to do it :)
All you need is that new language file. So I have asked another user with language that I need (and my watch doesnt suppor that region). Step One : connect supported watch to computer go to Files / Primary - Garmin - Text. And Copy that Language file. In my case it was Slovak.ln4. Step Two : connect watch you want to have new language pack, and go to the same TEXT directory. If you just past new language, you wont be able to see it in watch. So Step Three : delete one of the supporter language (for example delete Swedish.ln4) and rename your new language to deleted one (so I have renamed Slovak.ln4 to Swedish.ln4) and paste it to that text folder.) Step four : reset watch, change language to Swedish and you will have your new language :D