Hi there!
Let me first introduce myself - my name's Will Robertson, and I'm a contributor to the Rockbox project.
Rockbox is a replacement firmware for many MP3 players, including iPod, iRiver and Toshiba, as well as a bunch of others.
One of the strong points of Rockbox is its voicing support. Currently Rockbox stores MP3 clips of required strings in a voice file, however there has been a recent effort to build a TTS system in, to improve flexibility a bit. eSpeak was the best candidate for an embedded solution (and I must say I'm impressed with your work), however, we've hit a slight legal obstacle.
eSpeak (as you know) is released under the GNU GPL version 3, but Rockbox is licensed under GPL version 2 - the two of which are incompatible licenses unfortunately. I'm writing this mail to see if you'd consider (if it's feasible) releasing (or licensing) a GPLv2 version of the current eSpeak source.
There is an existing patch[1] which adds a simple eSpeak plugin to Rockbox which looks quite promising, but we'd like to get the legal issues out of the way before proceeding further in the matter.
I look forward to hearing a response. Thanks, Will.