Unhappy Keyboard Lagging/ Sticky/ Not showing up

So as my title states, my Xperia keyboard [Stock] is lagging after Ive typed for about two seconds, the keys/ letters starts to lag and causes massive delays, also, when I press the message box, the keyboard doesn't show up immediately, whereas I compared it to my friends Sony Xperia C, his keyboard pops up immediately.

Can anyone suggest any fix for me? I like the Xperia Keyboard, have tried other keyboards but theyre not THAT compatible and somewhat buggy..

Im on a 4.4.2 Firmware pre-rooted kitkat.. thanks

EDIT: Even the spell checker doesn't work -_- when I press the settings, nothing's inside.. Could anyone help me at least with the spell checker and make it work?