Phone apps language

FreePBX Phone Apps
1

Is it possible to change the language of a phone apps ? Change the language of voicemail apps from english to french ?
or would it be possible to do it by editing a certain file ?

2

Is your entire system set to French, but just not Phone Apps?

3

My asterisk is set in english.
voicemail are set in french or english depending on the user. (in application / extension / language code )
UCP is default english but can be set in french by user

Does that mean that the phone apps language is gonna be the default asterisk language ?

4

I am not sure what languages were done for Phone apps if any. @tm1000 would know best