1) It's a typo, yes. Thanks! 2) Well, they are lossy in the sense that pronunciation is context-sensitive. The number of cases where you actually turn the word into another word is very small: http://snowball.tartarus.org/algorithms/german2/stemmer.html has a discussion. 3) You are right, I'm wrong. ß, ä, ö, ü are considered part of the alphabet. It's not tought in school, though (at least not in mine).

Thanks a lot for making the effort and fact-checking better then I did there :).