RelaxNG with Son of ODD.

The Text Encoding Initiative is using literate schema design, as instantiated in the completely redesigned ODD system, for production of the next edition of the TEI Guidelines. Key new aspects of the system include support of multiple schema languages; facilities for interoperability with other ontologies and vocabularies; and facilities for user customization and modularization (including a new web-based tool for schema generation). In this paper, we try to explain the rationale behind the ongoing revision of the TEI Guidelines and how the new tools developed to go with it are taking shape. We describe the mechanics by which the new ODD system delivers its promised goals of customizability and extensibility, while still being a good citizen of a highly inter-operable digital world