double Dutch

double Dutch
    n 1: an incomprehensible talk
    2: the difficult version of jump rope in which players jump over
       two ropes that are swung in a crisscross manner by two
       turners
    

20 Moby Thesaurus words for "double Dutch":
      Aesopian language, Babel, Greek, argot, babble, cant, cipher, code,
      cryptogram, garble, gibberish, gift of tongues, glossolalia,
      gobbledygook, jargon, jumble, noise, scramble, secret language,
      slang