Finnish Spell Checker for System of OS X?
Download Voikko spell for 10.8-9 from

http://verteksi.net/lab/osxspell/

and put it in System/Library/Services  (not Library/Services or Home/Library/Services)

Go to Edit > Spelling and Grammar > Show Spelling and Grammar and set the dictionary to Suomi (not Automatic).

Also in Edit > Spelling and Grammar, check the items for checking and correcting spelling.

You should then see, for example in TextEdit, something like