> Sadly I could not find an emulator or tool online to input text and get a Voder audio output.

It seems like you'd need samples of the individual sound channels from the machine, and then a program to map the text to timed signals to produce the different sounds, along with pitch shifts, etc. Something similar to MIDI, maybe (vibrato, pitch shift, and the different sounds as different instrument numbers seems like it would work).

Part of the charm of the machine is the control the operator has to give inflections, tone, and timing. I think a text-to-voder emulator would miss a lot of the variation heard in the demo and would instead sound stale and less lifelike.