The study of language, as the study of any subject, is dependent on writing because the scientific enterprise is. The scientific world view assumes that the things and events that constitute the universe are understandable. Another fundamental assumption is that knowledge accumulates and progresses, that is, we know more now than people knew in Aristotle’s time. In the absence of writing people are not ignorant, but for science as we understand it, writing is indispensable. It enables scientific insights to be given permanence, separating message from messenger, text from author, judgement from judge, sentence from speaker. And it allows us to critically assess, take issue with, and build on the knowledge of our forebears. This chapter discusses the question of what writing means for the study of language, taking as its point of departure Ferdinand de Saussure’s critique of spelling conventions and its consequences for the evolution of modern linguistics. As in other scientific disciplines, in linguistics, too, writing is a major tool. However, what distinguishes the role of writing in linguistics from other fields of scholarship is that it relates to the object of investigation in complex ways concerning both the scientific analysis of language and the social conditions of its use. In literate society it is imperative to understand what the ‘tyranny of writing’ meant for the study of language when Saussure first used this term a century ago, and what it means today.