Gershwin called it "a rhapsodic ballet"; it is written freely and in a much more modern idiom than his prior works.
dʒˈɜːʃwɪn kˈɔːld ɪt "ɐ ɹæpsˈɑːdɪk bælˈeɪ"; ɪɾ ɪz ɹˈɪʔn̩ fɹˈiːli ænd ɪn ɐ mˈʌtʃ mˈoːɹ mˈɑːdɚn ˈɪdɪəm ðɐn hɪz pɹˈaɪɚ wˈɜːks.