Kiwat Hasinay Foundation - Non-profit foundation dedicated to keeping the Hasinay and Kadohadacho (Caddo) languages alive. - http://ahalenia.com/kiwat/
Caddo Language and the Caddo Indian Tribe - Pronunciation guide, language learning worksheets, and cultural information. - http://www.native-languages.org/caddo.htm
Wikipedia: Caddo language - Article including a phonological inventory and tones. - http://en.wikipedia.org/wiki/Caddo_language