What do, um, verbal slip-ups mean?

Have you, um, ever noticed, ur, uh, how people giving speeches often stumble or slip up when they get to key points? They might pause, state the wrong word, or forget to use a word. They may even slip up when they get to key points and repeat themselves. They might switch words around. They might combine two words and make them one.

Researchers have found that we regularly make verbal blunders — some say as high as one for every 10 words we speak; others put the number at one per 1,000. Blunders occur in every language, whether spoken or signed, and have been noted from ancient Greece through the infamous Reverend Spooner to our current error-prone president.

Although we often laugh at such errors, they tell us more than we realize, says author/linguist Michael Erard, in his engaging first book, "Um ... Slips. Stumbles, Verbal Blunders, and What They Mean." "In general, anyone who thinks or acts at the same time as they speak, especially under pressure, will blunder," writes Erard.

Consider the ever popular pause filler, um or uh. We use um more often when on a phone than face to face. Women and younger people, as well as those who gesture, say um less often.

We may view um-ers as bad or anxious speakers, but research shows that ums don't necessarily correlate with anxiety. Ums often appear when something else, such as an additional task, taxes your brain. Ums in conversational speech arise as part of a waltz, with speakers uming as a means to interact with a listener. Ums may also signal that the speaker is actively thinking and considering their word choices.

By focusing on what many of us overlook (or underhear?), Erard has further revealed the complexity and beauty of language. Perhaps he will make all of us both better listeners and, um, better speakers.