Why I Love Open Source
Can you imagine Microsoft or any other country taking the time and expense to inclue a spell checker for the Lower Sorbian language which is spoken by a Slavic minority in Germany?
Someone made such a spellchecker for Firefox.
It's not that I have any need for such spell checker, it's just that open source software is very flexible and repsonds well to the needs of its users. If you can't find a feature you like in your software, modify it yourself!