Multisite, multi language typing support

I am designing a baby blog site where parents can create their own baby sites. I want to enable them to write / Type in their own language. I have seen that they can do it by typing it on other language type pads supporting keyboards for multi language (on sites like http://gate2home.com/) and paste it here in the posts. But, I want the type pads to be integrated with their blogs.
For example, when they create their baby site, they will be prompted to select a language. Now they will be blogging in that language. Please let me know if this is available or please give me an idea for making this possible for my visitors.
Thanks in advance