Abstract Mandarin Chinese lexically distinguishes the disjunctors in alternative questions (háishi) and in disjunctive assertions (huòzhe), reflecting a distinction that Haspelmath (2007) and others have called interrogative versus standard disjunction. I argue that the two disjunctors share their basic syntax and semantics as junction heads (J) that project their disjuncts as Roothian alternatives, which are then interpreted by a corresponding question-forming operator or existential operator. I motivate this view from island insensitivity and focus intervention effects, which I show to apply in parallel to both alternative question formation with háishi and the scope-taking of huòzhe. Háishi also allows for a number of non-interrogative uses, subject to significant speaker variation. I argue that these patterns reflect broadly two types of grammars: those where háishi syntactically enforces that its alternatives be interpreted by certain operators, and those that do not. For the latter, more liberal speakers, háishi can be used non-interrogatively in the same environments that wh-phrases can be. The study and analysis of this pattern of variation leads to the conclusion that a so-called “interrogative disjunction” could be so specified via its syntactic specification or through its semantics alone, with both strategies being attested by different sets of Mandarin Chinese speakers.