World's fastest talker, Fran Capo, can utter 11 words per second.

She said she would memorize answers to questions for class and soon realized she could spit the responses out faster than her classmates.
Capo, who holds the Guinness Book of World Records for her fast talking ability, has appeared in more than 450 television shows and has also achieved four other world records, including the highest book signing (Kilimanjaro) and the deepest book signing (Titanic wreck site).
Source-ANI