In this thesis, I present and defend the hypothesis of invented languages (glossopoesis) as narrative frameworks in Science Fiction texts written in English. That means such invented languages play the role of ancillary devices in the storytelling process, rather than constituting occasional flourishment. An implication thereof is that they should be object of literary criticism and interpretation instead of pure linguistic analysis, as most preceding studies in the field have approached the matter. In view of that, I have divided the thesis into three sections according to their methodology. Section 1 is concerned with the definition of the three key concepts of Glossopoesis, Science Fiction and Narrative. Chapter 1 presents terms used by previous research in order to avoid polysemy while also tracing a historiographical panorama of invented languages in literature in English from the 1500s until contemporaneity. Chapter 2 presents theories on Science Fiction in an attempt to generate a taxonomic model that justifies the literary works I have chosen to work more closely with. Chapter 3, then, tackles notions that are relevant to the discussion on narrative. Section 2 is concerned with theoretical articulations. In light of R Cheyne (2008) and J R R Tolkien (2016), Chapter 4 revisits Stockwell’s (2006) research on the three functions of literary glossopoesis (elaborative, indexical and emblematic), expands on it, and offers two novel functions: narrative and cognitive. Chapter 5 articulates theories of interpretation as proposed by U Eco (1992), E D Hirsch (1967), Beardsley and Wimsatt (2002) and Eagleton (2003), to approach literary glossopoesis hermeneutics in a principled way. Finally, Section 3 introduces case studies. Chapter 6 examines how glossopoesis explores ideological issues in G Orwell’s Nineteen Eighty-Four (1949), U K Le Guin’s The Dispossessed (1974) and S H Elgin’s Native Tongue (1986). Chapter 7 broaches the extrapolation of language as weapons and ‘viruses’ in S R Delany’s Babel-17 (1966), I Watson’s The Embedding (1973) Jack Vance’s Languages of Pao (1956), and C Miéville’s Embassytown (2011). Whereas Chapter 8 investigates Brian Aldiss’s Barefoot in the head (1969), R Holban’s Riddley Walker (1980) and A Burgess’s A Clockwork Orange (1962) futuristic corruption of English from a readerly response perspective. The result will consist of a thorough and innovative criticism model of approaching works of fiction that feature glossopoesis.