Omniglot: Hopilàvayi - Hopi orthography and links. - http://www.omniglot.com/writing/hopi.htm
Hopi Language and the Hopi Indian Tribe - Pronunciation guide, language learning worksheets, and cultural information. - http://www.native-languages.org/hopi.htm
Wikipedia: Hopi - Article on the Hopi language including a phonological inventory and usage information. - http://en.wikipedia.org/wiki/Hopi_language
Ethnologue: Hopi - Basic demographic and linguistic information. - http://www.ethnologue.com/show_language.asp?code=hop
Hopi -na - Academic paper by Ken Hale on Hopi suffix -na. - http://www.museunacional.ufrj.br/linguistica/congresso/1/txhopi.pdf