I agree with Tony and Ken, and I would like to add that there were pretty
good POS taggers in the 70's, at least for French (but I think it is true
for English as well), as witnessed by Debili's thesis (I am not sure he is
on the list, but he can be contacted at <Fathi.Debili@ehess.fr>) :
Debili, F. (1977). Traitements syntaxiques utilisant des matrices de
précédence fréquentielles construites automatiquement par apprentissage.
Thèse de Docteur-Ingénieur, Université de Paris VII, U.E.R. de Physique, 297p.
Tempux edax rerum.