New spelling dictionaries?

Is there any way to have other spelling dictionaries?
I need a dictionary for Hungarian spelling. In Edit->Options->Auto-Corrrection in the downloadable dictionaries’ list there is no Hungarian.

And Latvian dictionary too, please. I find some Latvian aspell dictionary, but version 0.60.6, and it not work with old aspell 0.50 in Srivener. Maybe in future Srivener can works with hunspell dictionaries?