 The more general claim that illocutionary force is correlated by convention with sentence type has been advocated by Dummett (1973 [1981: 302, 311]). On this view, it is a convention that declarative sentences are used for assertion, interrogative for questions and imperative for commands and requests. Similar views have been put forward by Searle (1969) and Kot’átko (1998), and the idea has been more recently defended by Kölbel (2010). According to Searle (1969: 38, 40), illocutionary acts are conventional, and the conventions in question govern the use of so-called force-indicating devices (Searle 1969: 64) specific to each  language.[31]