I used to have a button with which I could switch the on screen keyboard to standard qwerty, reduced qwerty (no numbers), split thumb layout and handwriting recognition.
The button is still there, but it's blank and doesn't respond to my request to switch language or layout. Can't figure out what I did differently when I installed the Windows 8 CP this time round.
I found that I can switch both languages and layout on the Lock screen, but not once logged in. The choice I make on the log screen does translate over to the logged in session.