How many bps would be required to reproduce the words in speech recognizably?
This all depends how you interpret the requirements and what is "good enough". 

For example, a really bandwidth efficient  method would to simply encode with a speech to text system, send the text and re-encode with a text to speech system. That would be about 0.075 kb/s (150 words per minute, 6 letters per word, 5 bits per letter). 

That would make a pretty terrible speech coding system but whether that meets the "rules" or not is more a semantics than a technical question.