TL;DR
To change your interface language, click your avatar → Settings → Language choice → pick your language → Save.
Overview
You can change the language used throughout your interface from your profile settings.
How to Change the Language
- Click your avatar in the upper-right corner 1.
- Select Settings 2.
- Click Language choice 3.
- Select your preferred language.
- Click Save 4.
Your interface updates to the selected language.