That quote from Schnee seems odd to me. I mean, what do you get if you try to decompile the binary? That output should be more useful than "a database of every phoneme it had ever uttered".

And, as someone else pointed out in this thread, there exists an ISO and an activation code at archive.org, and it should be possible to get this running in Wine or in a VM. Someone clever could probably patch the binary to make it run on modern Windows. The distraught rabbis should community-source a developer.

All of that said, even if the source code were to be found, it seems likely that further development of the core functionality might be dead. This was a man's life's work in an esoteric domain; it might not exactly be accessible code.