The languages in the Apps are determined by the settings on your phone. If you change the language for your phone, the App will follow. However, currently the Apps only support the following languages:
English
French
German
Italian
Spanish
Japanese
The default language display is English so this is what you will see if your language is not supported.
IOS
You can change the language for the App directly in the App settings. Tap your phone's Settings then GuideMichelin > Preferred Language where you can select any language you prefer.
ANDROID
For Android users, you will need to change your phone's default language to change the App's language display.
Note that changing the language does not necessarily change all the restaurant & hotel descriptions. There are cases where translations are not yet available.