Salve,
it`s probably a little early to share ideas of audio outputs, but these ideas could be interesting for Wiktionary, too - or I would be happy when non, German speakes would be interested in:
Wiki Project "Spoken Wikipdia" - the aime is to speak Featured articles and recod this digitaly. This would maybe interest the same people which like audiobooks, blind people and people which like to learn a language: http://de.wikipedia.org/wiki/Wikipedia:Wikiprojekt_Gesprochene_Wikipedia
I try to start a project "Wikipedia for blinds", which has the aim to take care that the user-interface of the Wikipeadia is blind user friendly, and shared some ideas for synthetic speach output on PC, internet audiostream and telephone: http://de.wikipedia.org/wiki/Wikipedia:Wikiprojekt_Wikipedia_f%C3%BCr_Blinde
Synthetic speachoutput is IMHO not good engough for the Wiktionary, but both projects could bring ideas for the Wictionary interfaces and maybe people who like to speak and record word pronunciations *g*
rob