As we feeel the core system has reached an acceptable level of maturity from 1.4.0 the basic system is released under a free lience, without the commercial restrictions we imposed on early versions. The basic system has been placed under an X11 type licence which as free licences go is pretty free. No GPL code is included in festival or the speech tools themselves (though some auxiliary files are GPL'd e.g. the Emacs mode for Festival). We have deliberately choosen a licence that should be compatible with our commercial partners and our free software users.
However although the code is free, we still offer no warranties and no maintenance. We will continue to endeavor to fix bugs and answer queries when can, but are not in a position to guarantee it. We will consider maintenance contracts and consultancy if desired, please contacts us for details.
Also note that not all the voices and lexicons we distribute with festival are free. Particularly the British English lexicon derived from Oxford Advanced Learners' Dictionary is free only for non-commercial use (we will release an alternative soon). Also the Spanish diphone voice we relase is only free for non-commercial use.
If you are using Festival or the speech tools in commercial environment, even though no licence is required, we would be grateful if you let us know as it helps justify ourselves to our various sponsors.
The current copyright on the core system is
The Festival Speech Synthesis System: version 1.4.0 Centre for Speech Technology Research University of Edinburgh, UK Copyright (c) 1996-1999 All Rights Reserved. Permission is hereby granted, free of charge, to use and distribute this software and its documentation without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of this work, and to permit persons to whom this work is furnished to do so, subject to the following conditions: 1. The code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Any modifications must be clearly marked as such. 3. Original authors' names are not deleted. 4. The authors' names are not used to endorse or promote products derived from this software without specific prior written permission. THE UNIVERSITY OF EDINBURGH AND THE CONTRIBUTORS TO THIS WORK DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE UNIVERSITY OF EDINBURGH NOR THE CONTRIBUTORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.