In this paper we will show and defend the benefits of using multilingual markup schemes for large digitization projects, such as the Miguel de Cervantes Digital Library, and the consequent increase in production due to using markup tags in one's own language. We will also show the process carried out in designing the scheme and developing the parsers and programs for the generation of Extensible Stylesheet Language (XSL) transformations and C parsers to convert English markup and Document Type Definition (DTDs) to Spanish. Finally, we will adduce the conclusions of the implementation of this project.