Hey,
How hard would it be to come up with these word-stem normalizers for other languages (i.e. did you base Esperanto off of another similar language or did you come up with it yourself relatively easily)? Is there a good description somewhere on how to come up with them?
That may require some linguistic abilities and some coding abilities :) There are several stemmers floating around, with one being used by various opensource software - snowball (http://snowball.tartarus.org/). It has English, French, Spanish, Portuguese, Italian, German, Dutch, Swedish, Norwegian, Danish, Russian, Finnish supports. Maybe there's possibility to adapt rules from there.
Cheers, Domas