Adding foreign language Dictionary.

[remote]

Hi I would like to know if it's possible to add some other languages
into the Spelling Dictionary.
I'm Italian so it would be very useful for me to have an Italian
Dictionary.
BTW it's possible to add single words to the Dictonary and I'm
wondering if coul'd be possible to add more then 1 word at once.
I'm relatively new to the mac platform and I do not understand where
these words are stored.
If they go to an external file maybe it would be possible to edit this
file and add a whole free dictionary to it.

Thx.

remote : Luigi Cristiano