The Myth: Women use many more words per day than men. The numbers vary—some sources indicate women use about 7,000 words a day compared to only 2,000 for men, while others count as high as 24,000 for women and 10,000 for men.

The Truth: "Complete fabrications," says University of Pennsylvania linguist Mark Liberman. "No reputable study has ever measured the widely repeated numerical comparisons that show women talking two or three times as much as men." And the research that has been done shows no significant gender difference, with perhaps even a slight edge for men.

Sexism is behind much of the willingness to believe that women talk too much, according to Deborah Cameron, a professor of language and communication at Oxford University, who points to "the belief that women really should be silent, as recommended by ancient authorities ranging from Sophocles to St. Paul." She also blames "the popular psychology industry, which loves pandering to stereotypes to sell books."

Though much attention is given to male versus female communication styles, there is more variation between individuals than between genders. "This is hardly surprising," Cameron says, "as the main influences on how much people speak are contextual—what they're doing and with whom."