Is it possible to restrict language of virtual keyboard, or SIP, to a English only? I'm developing a multilingual game with Scoreloop and want to allow users to enter their nicknames in latin only.
I don't think it is possible, but if it were you shouldn't.
Leave the keyboard language selection to the user. It would be very confusing for the user to suddenly have a different SIP.
Just validate the string that is entered.
EDIT
You are not looking for an input language but for a character restriction so another option is to design your own SIP with the characters you want to allow