Here is a reply from a forum's member in another thread. I think, this is the problem:

The problem is, that espeak is in an inconsistent state in the extras repository. [1]
The newest version of the espeak package there is 1.46.22, while for its dependencies espeak-data and libespeak the newest version is 1.46.27. espeak needs exact version matches for its dependencies, but since apt-get tries to install the most recent version, this creates a conflict that can't be resolved.

dirty stopgap:
A: Manually download and install the three packages in version 1.46.22.
B: Install espeak from extras-devel, where espeak is in a consistent state. [2]

I need versions 1.46.27 from espeak, espeak-data and libespeak. If I want do download and install from extras-devel, which version is right for me: i386.deb or armel.deb?

Edit: I found the answer myself. BUT: If I try to install libespeak 1.46.27 from here: http://repository.maemo.org/extras-d...free/e/espeak/

App-Manager will NOT install it, cause the catalogue (repo) is not compatible... I have enabled all repos on the phone: CSSU, CSSU testing, CSSU devel and CSSU thump...

Any idea?

Thanks!