Webui multilingual? At present, I see that only English is supported
It’s not going to be happening particularly soon.
The Incus UI is currently based on the LXD UI, so if the LXD UI had support for translations, then we’d have it too and would try to get folks to translate the few additions and tweaks we’ve made on top of it.
But as that’s not the case, it would likely have to wait until we eventually have enough resources to make a UI fully of our own.
Unfortunately I’m also not sure of how successful that would be. Despite a large-ish user base and full support for translations, the Incus CLI hasn’t seen that much interest from translators. Currently the only language that has a usable percentage of translation for the CLI is Japanese with around 75% of all messages translated, the second best is Chinese at 33% which is in my opinion too low to be useful for most users as it will literally be a weird mix of Chinese and English throughout the CLI.
Basically, good translations either need a huge community so enough folks contribute and most common languages can be at the 90%+ translation range, or you need a massive commercial entity who can afford to pay a full team of technical translators.
As it stands, we have neither 
Well, thank you.