Finnish Spell Checker for System of OS X? I know this discussion about spell checkers for Pages, here. 
I am searching for the files ending with .aff or .dic.
Without them, you cannot use them in system. 
My current OS X is Yosemite 10.10.2.

The manual of OS X says that in Settings &gt; Keyboard &gt; Spelling &gt; Set up ...


  To add an additional spelling dictionary, copy the dictionary files (.aff and .dic) to the Spelling folder in your Library folder.


Is there any standard dictionary for Finnish?
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