And Basque?
Well, such task is a lot of work, and since most people coming there can read English, they probably don't feel the need to make a translation.
The fact that the doc. is huge and extensive is quite intimidating too...
Something that could be done, too, is to provide a way to localize the AutoHotkey interface (context menu, windows...), using text files.
It has been done for SciTE, for example, and it works quite well, that's not too hard to do - the resources and internal strings are hardcoded in English; strings goes through a function call that translate them if needed, interface is translated on the fly.
Perhaps someday I will take a look at this.