Families of Categorial Languages Makoto Kanazawa 1 National Institute of Informatics Tokyo, Japan We show that the class of string languages generated by abstract categorial grammars is a substitution-closed full AFL. The result also holds of each class G(m, n) in de Groote's hierarchy. We also show that the class of string languages generated by lexicalized ACGs is a substitution-closed AFL, and that most of the results about string languages carry over to tree languages. s: Abstract Categorial Grammar, Abstract Family of Languages, Tree Languages.