Lawmaking is - paradigmatically - a type of speech act: people make law by saying things. It is natural to think, therefore, that the content of the law is determined by what lawmakers communicate. However, it is sometimes vague what content they communicate, and even when it is clear, the content itself is sometimes vague. In my dissertation, I examine the nature and consequences of these two linguistic sources of indeterminacy in the law. I argue that vagueness in the law is sometimes a good thing, although its value should not be overestimated. I also propose a strategy for resolving borderline cases, which - if correct - sheds significant light on the debate about legal interpretation.