Due to the enormous development of science and technology in recent times, English has become the leading language for conveying specialised knowledge. Conversely, in Galicia, the study of specialised discourse has remained largely unexplored until the very end of the last century, when Galician achieved the status of co-official language within the Spanish State. This article presents an analytical and descriptive approach to the notion of specialised discourse with three objectives. First of all, it attempts to clarify the aforementioned concept, as well as its distinctive features, in order to identify potential differences and similarities in terms of how experts belonging to the English and Galician-speaking worlds understand and use specific-domain languages. Secondly, it aims to conduct a quantitative and qualitative corpus-based comparison of the most relevant morphosyntactic features in English and Galician specialised discourse, with a particular focus on the field of medical writing. Lastly, this article also intends to fill a significant gap in Galician linguistic studies, where research on specific-domain languages remains a pending issue. To attain these objectives, a corpus-based cross-linguistic comparison of English and Galician specialised discourse is carried out based on twenty-four research articles. By means of which, the most representative morphosyntactic characteristics of specialised texts are analysed, interpreted and discussed in depth for both languages. The results reveal that English and Galician domain-specific languages present far more similarities than might be expected at first, the most notable differences being those inherent to the specificity of each linguistic system.