In this article, I look at the connections between the eminent linguist Edward Sapir (1884-1939) and modernist poetry. In his career, Sapir provided extensive knowledge about North American languages and promoted an influential relativistic approach to language and culture. His understanding of language, particularly its cultural values, was informed by his understanding of literature. I look, in particular, at the ways that Sapir applied his theories of language to his contemporaries in modernist poetry, with specific focus on Amy Lowell and Hilda Doolittle. Sapir saw modernist poetry as being based on the same linguistic principles as his broader theories of language and culture. I argue that Sapir's theoretical writing is not simply a key by which we should read modernist approaches to language, but is made up of important literary connections which point to his influence and standing in the modernist network.