I agree it makes the extension pretty unusable for non-english speakers (even when speaking english at my so-so level, you don't find easily the obvious/current expressions for each emotion).
(Just a note, there is another little difficulty (without obvious solution) in french: the automatic smiley menu starts as soon as there is a
: after a space, but in french typo, all the
: must come after a space. So in french it basically starts each time the
: is used.)