import itertools as it

lang1 = {'a', 'aa'}
lang2 = {'b', 'ab'}

lang1lang2 = set([''.join(parts) for parts in it.product(lang1, lang2)])
lang2cubed = set([''.join(parts) for parts in it.product(lang2, repeat = 3)])

print("lang1lang2 = {0}".format(lang1lang2))
print("lang2cubed = {0}".format(lang2cubed))