I propose to enquire here into the way we endow our speech with meaning and into the way by which we make sense of speech that we hear spoken. I shall show that, notwithstanding their informal character, these acts possess a characteristic pattern, a pattern that I shall call the structure of tacit knowing; I shall show that to form such a structure is to create meaning. Both the way we endow our own utterances with meaning and our attribution of meaning to the utterances of others are acts of tacit knowing. They represent sense-giving and sense-reading with in the structure of tacit knowing. My enquiry shall outline the total structure of language, comprising both its formal patterns successfully established by modern linguistics and its informal semantic structure, studied so far mainly by philosophy.