The Vector Watch app

At this point, the Windows Vector Watch app is available in English, while the iOS and Android version is available in English, French, German and Spanish.

Your Vector Watch app will inherit the language setting from your phone, and default to English.

The notifications you receive

When someone sends you a notification or calls you, you will see it displayed on your watch. The supported languages for notifications and caller IDs are:

VOS (Watch version) v1.0.0

English
French
German
Spanish
Italian
Romanian

VOS (Watch version) v1.1.0 (and higher)

Bosnian
Croatian
Czech
Danish
Dutch
Estonian
Finnish
French
German
Hungarian
Icelandic
Irish
Italian
Latvian
Lithuanian
Luxembourgish
Maltese
Norwegian
Polish
Portuguese
Romanian
Serbian
Slovakian
Slovenian
Spanish
Swedish
Turkish

So messages like "J'y suis arrivé" or "¿Que hora es?" should display just fine.

The Event Name stream

Similar to notifications, event names with special characters will display just fine in the languages supported by the notifications system.

The watch streams, apps & user interface

At this point, for Windows Phones we only support English on the watch, while for Android and iOS we support English, French, German and Spanish.