Up Arrow -> Previous match
Down Arrow -> Next Match
TAB -> Accept suggested word
ESC -> Toggles the auto complete
So, Word Complete auto completes words based on the characters the user has typed and shows them by autocompleting, but as selected.
There are 28 languages that is supported with, including special characters specific to the languages.
I have chosen to limit the dictionary size to ~30 Kb, but there isn't any noticeable change in performance with bigger dictionaries.
One upcoming feature is red waves under unrecognized words.