Why does it say LUIBUTTON_SWITCHUSER and LUIBUTTON_CANCEL in unlock screen?

Normally in the unlock screen it says "Switch User" and "Cancel" at the bottom, but now it says LUIBUTTON_SWITCHUSER and LUIBUTTON_CANCEL. The text box says SECURE_TEXTFIELD_PL. I haven't noticed any other places where things are rendered strangely. Any particular reason why this happens, and is there any fix that doesnt involve me nuking the computer?