or formality (Fan et al., 2017;Hu et al., 2017;Ficler and Goldberg, 2017;Shen et al., 2017;Herzig et al., 2017;Fu et al., 2018;Rao and Tetreault, 2018).
human language actually involves a constellation of interacting aspects of style, and NNLG models should be able to jointly control these multiple interacting aspects.