[Settings] Language feature missing

**Accessibility and user control requirement**

While platform can inform language, user must have the option to change or override the system default in-app.

Use case example: User profile is set to USA app market and English language, but prefers to use this experience in Spanish. #254

Start by reading issue #254 and tracing how the app currently derives its language from the platform and user profile settings. Done means a user can override the system or market default in the app and select Spanish, with the resulting experience reflecting that choice.

Written by the indexing model from the issue text.