Can't enter password due to changing keyboard's language and stuck with it

For some reason, I changed my keyboard to Greek, yet my password is in English. I am unable to enter the password to unlock the phone. I can't pair with Bluetooth without unlocking, and there is no option to change the language of the keyboard. The device is a Sony Xperia Z, Android 4.4, not rooted, and using the default keyboard, if it's relevant. Any help is greatly appreciated.