In applied communication studies warnings (as components of instructional texts) are often characterized in terms of criteria for effectiveness. An idealised model for warnings include the following elements: a signal word or label appropriate to the level of hazard; a hazard statement; references to the consequences of failure to comply, and an instruction on what to do or not to do to avoid the hazard. This contribution is firstly aimed at demonstrating the comprehensiveness of the Wogalter model by exploring the semantics of the speech act verb WARN and the verbs underlying the constituent elements of the model, namely POINT OUT/ALERT, INFORM/REMIND and INSTRUCT. The analyses depart from speech act theory, making abstractions at different conceptual levels to demonstrate that WARN is a complex speech act subsuming lower level speech acts such as POINTING OUT/ALERTING, INFORMING and INSTRUCTING. Secondly, the model is used to analyse and evaluate actual warnings collected from information sheets for hair-dryers, indicating the heuristic value of combined insights from document design and speech act theory.