fomo is available in seven languages: English, Deutsch, Español, Français, 中文, 日本語 and Português (Brasil). You pick the language in Settings, and the choice stays on that device until you change it.
How to change it
On the mobile app, open the Portfolio tab (the tab with your avatar) and tap the gear icon. On the web app, hover over your account at the top right and choose Settings.
Tap Language.
Choose a language. On the mobile app you can also choose System to follow your device language, and that row shows which language it detected. The web app has no System option: it follows your browser language until you pick one.
The change applies right away to fomo's own screens. Theses and comments from other traders are translated into your app language automatically, and each one has a Show original toggle if you want to read it as written. Your own posts are never translated.