Firefox (www/firefox)(version=15.0) doesn't use dictionaries from /usr/local/share/hunspell, only from /usr/local/lib/firefox/dictionaries, and, of course, xpi.
By default firefox builds with --enable-system-hunspell.
pkg_info -R hunspell-1.3.2_1
But it hasn't worked for ages.
Fix: Patch attached with submission follows:
How-To-Repeat: install firefox, russian/hunspell.
run firefox and try spell checking. You won't see Russian in Languages list.
Over to maintainer (via the GNATS Auto Assign Tool)
Should be fixed in r305684