... Its assumption that children are born with innate linguistic knowledge termed Universal Grammar (UG) and the subsequent Principles and Parameters framework is widely used in language acquisition research (Kania, 2016). Particularly, children question formation which involves inversion (or movement) has attracted many researchers' interests (Santelmann et al., 2002), and their research in inversion and child question formation make great contributions for constructing and improving generative account of child question acquisition (e.g., Borer & Wexler, 1987;De Villiers, 1991;Erreich, 1984;Ingram & Tyack, 1979;Klee, 1985;Klima & Bellugi, 1966;Kuczaj, 1976;Labov & Labov, 1978;Radford, 1990Radford, , 1994Rowland, 2007;Theakston et al., 2001Theakston et al., , 2005Valian, 1991). Specifically, many generativists propose that inversion or movement is an essential component of UG which is constantly available to children (e.g., De Villiers, 1991;Stromwold, 1990), and children could utilise this innate linguistic knowledge to form adult-like questions from the very beginning of the language acquisition process (Rowland, 2007;Theakston et al., 2005). ...