[ruuk]

espeak seems not to talk on the command line but that should be fixable.

I think you would need to add alsa or something to the openelec Raspberry Pi version, which I don't think is going to happen.

so when we have audio we might even be able to use espeaks c++ library directly via python.

This works but is unstable. Crashes XBMC when changing voices or re-loading the backend. We've tried a to make it work, but have given it up as probably unworkable.

we also have the thing that we are running everything from the sd card. so reading and writing wav files all the time is a bad thing to do. so if we can eliminate this that would be a good solution which saves us maybe 1-2 seconds which can cause this lag.

If we can't get audio out, we can make an option to set the path for the wav files. This could point to an external USB drive or ramdisk.

the service seem to crash while i am in the addons settings dialog.
in other windows i don't know. i had a pretty nice lag so i haven't tested further but will do.

What do you mean by the service crashes? Does XBMC crash, or does the service stop speaking?
Also, if you load the old eSpeak which uses ctypes, it will crash XBMC when changing settings (as alluded to above). It has been marked as broken on the most recent versions and disabled.

where are the logs for the tts addon stored

The logs are in the XBMC logs. I don't know where that is with OpenElec on the Pi, but it might be in ~/.xbmc/temp/xbmc.log.
You can also share the log with the XBMC Log Uploader addon.