It has often been said that a psychologist by the name of Albert Mehrabian proved that words account for only 7% of public speaking whereas 38% is about tone and 55% is about body language. This is untrue, a ‘public speaking myth’, and misrepresents his work. What Mehrabian actually said was that this formula only applies to communication about feelings and attitudes. It was based on studies of simple personal communication of individual words and phrases and might apply to situations where a simple response to a question, such as a “Maybe”, or a “No”, is less believable than the tone or body language might indicate. See a humorous presentation of this here or Mehrabian’s own view of his research here.
It is helpful to be clear of our facts, but surely no-one could reasonably believe that 93% of public speaking effectiveness could have nothing to do with its content! On the other hand, most men probably discover the hard way that their grunting and shoulder shrugging communicates a little too much of the wrong thing!