"The editor Vim supports Unicode natively. If your X or console
keymap is set up to enter unicode characters via the keymap, it
will work fine in Vim. Alternatively, there are two other ways of
entering these characters."
"The slow way is just to use their hex code. Hit Ctrl+V, then u,
then type the hex code. For example, hex code 00BF will give you an
inverted question mark, Â¿. This is useful if you only
very occasionally want to type one of these characters. Lists of
UTF-8 character codes are available online."