In the Camuno dialect of northern Italy, ‘do’‐support may be used to form the interrogative. In some varieties, this is optional, and it co‐exists with the alternative interrogative method of using the main verb alone. Through an elicitation experiment, participants produced their preferred version of a question based on a certain main verb with given context. The likelihood that ‘do’‐support was used varied according to the supported verb's semantics and the context pragmatics, specifically: (a) the degree to which the verb denotes activity (directly or indirectly); and (b) the role of the subject as an effector, or ‘do’‐er of that activity. Unlike for ‘do’‐support in English, a purely syntactic function does not seem relevant for Camuno ‘do’. The study shows that: (1) even if, syntactically, the support verb resembles an auxiliary, it may have full lexical content; and (2) that there exists a credible grammaticalisation pathway from a lexical ‘do’ verb to a semantically bleached, contentless ‘do’, seemingly motivated by a social preference for the ‘do’‐support construction and a desire to simplify the interrogative system.