I could build debs with and without espeak, but they're either-or. Once the debs are made that's it as they are a binary release, not a source release. I'll see about putting together source debs as well.
We could add a patch and make espeak a command-line or config-file option, or if there's a way to detect when it fails to initialise that Oolite just logs that but continues on anyway with espeak disabled.
The report you've had - does that mean Oolite fails to start completely?