list_member(X,[X|_]).
list_member(X,[_|TALL]):-list_member(X,TALL).
isVowels(A):-list_member(A,[a, e, i, o, u]),!.
isConsonants(A):-list_member(A,[b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, x, w,y,z]),!.
word:- write('Enter the word you want to know weather it followed by a an or the:.'),read(X),nl,
plular(X):-((isVowels(sub_atom(X, _, 1, 0, C)))->(write('Plular form of '),write(X),write(' is '),write(X),write('s'));(write('Plular form of '),write(X),write(' is '),write(X),write('es'))).