The formalist perspective on language acquisition Yang outlines may be ‘personal’ (Yang, 2018, p.1), but it offers a valuable illustration of the spirit guiding much 21st-century generative work. Central here is the drive to “reduce[] the explanatory burden traditionally placed on innate linguistic parameters” (Yang, 2018, p.5) by pursuing a three- (1a) rather than two-factor (1b) model of grammar acquisition and structure