In the last forty years, fan-fictions, derivative writings openly based on published works of fiction, have gone from being shared on semi-secretive zines circulating between a handful of people, to being hosted on public online archives, such as Archive of Our Own with 6 million registered users. At the same time, fan studies have grown into an interdisciplinary and transnational field. However, linguistic approaches to fan studies and fan fictions have always been quite marginal, and even more rare are the linguistic works investigating the use of conlangs in fan fictions. With a corpus-based approach, this study aims to analyse how fanfiction’s authors use Tolkien’s conlangs in their works, focusing in particular on the use of Quenya, by far the best documented language of Tolkien’s Legendarium. The analysis gathers its empirical evidence from a corpus of publicly available fan fictions from AO3, all of them written in English with an explicitly stated use of Quenya. This investigation will have two main focuses: a) a pragmatic analysis of code-switching from English to Quenya and its stylistic purpose in Tolkien-inspired fanfictions; b) an analysis of the formal characteristics of Quenya in fanworks, aimed at verifying the authors’ level of knowledge of Quenya and (possibly) the sources of such knowledge.