All languages share certain categories of expression which seem to correspond to a constant model. The forms which these categories assume are listed and classified in linguistic description, but their functions become clear only when they are studied in action—in the practice of language and the fabrication of discourse. These categories are fundamental, independent of all cultural determination. They reveal the subjective experience of speakers who establish and situate themselves in and by language. Our effort here will be to clarify two basic and necessarily associated categories of discourse, that of person and that of time.