... learning Italian, a pro-drop language (Valian, 1991) and Chinese, which allows 'topic-drop' (Wang et. al., 322 1992), as compared to English-speaking children of the same age and ... grammatical explanation of the null-subject stage. Both Lillo-Martin (1991) and Rizzi (1994), for example, argue that the initial value of the parameters is set to (- pro-drop); Lillo-Martin ... incorporates several standard assumptions of Principles-and-Parameters theory including X' structure-building capacity (Chomsky, 1981), head- complement ordering parameters, and several parameters...