A verbal typo is the result of a well meaning person trying to say something coherent but tripping over his or her own mouth in the attempt. Generally, a verbal typo is similar in appearance to the intended word when written down, but when spoken it sounds twisted and often hilarious.
A verbal typo is when someone says something other than what they wanted to say in the first place. It is most often a switching of prefixes between two words, such as "chicking tock" instead of "ticking clock". It can also be an entirely different word that just sounds the same. Verbal typos occur a lot, and can happen to anyone at any given time.
John: Damn, I can't concentrate. That chicking tock is so annoying!
Jane: What's a chicking tock?
John: Sorry, ticking clock. Just made a verbal typo.