static Map<S, Set<S>> ai_englishWordCategoriesWithElements() {
  final Map<S, Set<S>> wordCategories = ciMap();
  for (S cat : mL("All english word categories"))
    wordCategories.put(cat, combinedMechSetsCI(ai_mechListNamesForAngleBracketCategory(cat)));
  /*for (S cat : keys(wordCategories))
    print(cat + ": " + l(wordCategories.get(cat)));*/
  ret wordCategories;
}