In 2006, the Language Technologies Unit at Bangor University produced a synthetic text-to-speech voice for Welsh as part of the WISPR project. This basic version of the voice was released under a free BSD-style license, along with the associated development resources. This license was chosen deliberately to allow commercial companies to develop and commercialize their own products based on these resources.
This strategy proved successful, and now several companies are developing commercial Welsh voices based in part on some these resources. To contribute further to this work, Bangor University has decided to release further improvements to the TTS rules under a free BSD-style license to SALT Cymru members.
These improved rules (which were previously part of a commercial package offered by the University) include tokenization rules and a list of exceptions (words where their pronunciation differs from what would be expected from their written form) along with their part of speech and correct pronunciation.
You can download the resources here: