Good question, and the answer is a bit of a relief: that is a website limit, not a product limit.

The site UI ships in a few languages because of where our early users are. The analysis itself is not restricted to them. You can generate a profile in any language you write in. The stylometric model reads whatever samples you give it, and each profile is built only from your own writing. We have built profiles in languages that are not in the UI at all, including Chinese.

So if you write in a language that is not in the menu, it still works. Give it your samples, and you get a profile.

What language are you writing in?