Originally Posted by EI-MICK
I think its the engineers from the companies who manufacture the systems eg honeywell and some are computer generated.
The Honeywell EGPWC uses a Texas Instrument voice chip IIRC with over 640 "voice" combinations. We were told that the Voice Alerts on the Rockwell-Collins EICAS fitted to our CRJs was recorded by a local Cedar Rapids (CID) television personality - although I've always thought the particularly annoying "NOSE DOOR" was by the original systems buyer - it's got a definite Canadian accent!
Tones (on classic 737s & similar era aircraft) came from a special Pacific Electrodynamics generator and have become pretty much the standard even though digitally produced now. The only new tones are the "Attenson" (BONG) which was a specific waveform from the CAA which also required & codified the Autopilot Disconnect "Cavalry Charge".