The web page refers to a developer site offering professionally recorded, pre-recorded audio prompts for phone applications. The prompts, which include various categories like airlines, alphabet, credit cards, and numbers, are released under the LGPL open-source license, and are available for free download in the 8,000 Hz, 8-bit, MuLaw .wav format. Users can either download the entire audio library or select specific files based on their requirements.
VoiceXML and CCXML Developer Site