The free/open-source development model has been adopted by many machine translation (MT) researchers and developers who are opening their code to the community. This benefits, on the one hand, machine translation users who have access to machine translation software that they can adapt to suit their needs, and, on the other hand, to machine translation researchers and developers who get valuable feedback to improve their systems.

Machine translation systems mainly depend on both algorithms (translation engines) and data (linguistic rules, parallel corpora, etc.). Hence, not only the implementation of the algorithms must be free/open-source, but also the data themselves. Nowadays, there are many machine translation packages of this type available, but most of them are corpus-based, and, in particular, statistical machine translation systems (SMT): rule-based (RB) systems built on these principles are still little known. Both SMT and RBMT paradigms have pros and cons and none of them can be identified as inherently better than the other; in fact, hybridisation is currently an active field of research

An advantage of having free/open-source licences for rule-based machine translation is that the linguistic knowledge can be reused to build knowledge for other language pairs or even for other human language technologies besides machine translation, and, conversely, linguistic knowledge from other sources may be reused to build machine translation systems. The free and open scenario makes this reuse easier, and, if copylefted licences are used, builds a commons of knowledge and resources that benefits all the language communities involved, and specially less-resourced languages, for which large bilingual corpora are not available, and morphologically rich languages, which even with large corpora suffer from data sparseness.

With the aim of gathering together free/open-source rule-based machine translation practitioners and users, the First International Workshop on Free/Open-Source Rule-Based Machine Translation was held in November 2009 at Universitat d'Alacant (Spain). After the success of the first edition, a second edition will be held at Universitat Oberta de Catalunya (Barcelona, Spain) in January 2011.