Return of Reckoning

I know that I've seen video/streams of people playing in Europe and they have alternative letter characters in their name. I wanted to ask if those characters are available to use in the US when naming your character? Here's an example of what I'm talking about: ì, í, î, ï

I don't think you can have them in your character name, but you can in your last name. At least I know ä and ö can be used.