Cecil, W5DXP wrote:
"What Baud rate would be required for a human to copy RTTY by ear?"

The Baud rate is about twice the bandwidth according to Bell Labs`
Nyquist. Then Shannon, also of Bell Labs came along saying information
could be transferred much faster if the signal to noise were 30 dB or
better.

Using the standard Baudot or Teletypewriter code, about 8.000 words per
minute can be transmitted.

Operators who can copy Teletype by ear are likely to be rare indeed.

Best regards, Richard Harrison, KB5WZI