If you have localized your app content into different languages, you can detect the locale of the user at runtime using the platform SDK. Then, use the locale to determine what language version of your app content you offer that user.
You can get the locale of the logged in user with a call to the platform GetLoggedInUserLocale function.
For example:
const char* locale = ovr_GetLoggedInUserLocale();
// Do something depending on locale value.
The return value (locale in this example) is a language-country code string that conforms to BCP 47. This means you can expect a language subtag, a dash, and a country/region subtag. For example, “en-US” represents United States English.
Use the returned locale string to decide what language your app should display and use for this user.