Stephen Barker sets out and defends a radically new semantic theory, and shows how it solves notable problems in the philosophy of language. According to the theory, linguistic meaning should be understood in terms of speech acts, and the fundamental bearer of truth is not a proposition but an assertion. Barker sets this theory in a broader philosophical framework, including a simple, common-sense ontology and an account of pre-linguistic mental representation. This is an ambitious, rich, and original view of language and its world.