M-48
Your language, and where it follows you
English, Hindi and Tamil, chosen from the top of any page or from the app's More tab. The choice is kept on your account, so it follows you from the site to the app to the desks, and a link someone sends you opens in your language rather than theirs.
Where a translation has not landed yet, the page falls back to English rather than showing you an empty space. That is deliberate: a missing word should cost you nothing.
Ustad answers in the language you write in, and the Circle keeps each answer in the language it was written in rather than translating it, because a mechanic's own words are usually clearer than a translation of them.