first that option was completely missing, I couldnt find it anywhere in settings. one day it magically appeared. over time I had added a bunch o' words to it, today went to add one more, but under "edit user dictionary" it says NO WORDS and the + button is nowhere in sight. wtf is going on.
You need a Chinease Language keyboard selected. (forget which one, something with a "p") Then it should appear in "Keyboard" in General