Sometimes you just forget what you're going to say, and that brings us to the topic of this video—um. Why do we have these disfluencies? Well, it usually signals a lag in production. We're just trying to sort out the right word to say. Now, when we speak, we're constantly shifting between planning what we're going to say and executing that plan. Now, in normal fluent conversation, we produce two to three words a second, and we're choosing these words from a huge library we might know anywhere from 50-100,000 different words. So picking the right words and putting them in the right order is a pretty complicated task, and an um just sort of signals a bump in the road. Now, in this way, um is different from other disfluencies. So we often can, we often will restart a sentence once we figure out the correct syntax. Now, these self-repairs are a little bit different from um, but they are in the same basic pallbark, ballpark. That's a spoonerism, by the way. So on a spoonerism, we invert two different sounds, and this is another type of production error. It's not necessarily one based on the need for more time maistly. Oh, that's another production error. That's a blend. I hear we have two words that show up as possible choices in this case mostly and mainly. We can't figure out which one to use, so we blend them together, maistly. Okay, I'm done. You sure? Oh, yeah. Go back to the first guy. Many of these disfluencies mean that we need more time to plan out the utterance. A seminal article even argued that um carries meaning. It means, "Hey, expect a small delay in what I'm saying. I'm not done just yet, so don't stop paying attention." So in this way, ums serve a function. Now, that's not to say we don't want to reduce them, but ums can actually help listeners. In fact, in one study on um, listeners had to identify words from a spontaneous speech. So one group listened to a speech with ums present, and then the other group listened to the same speech with the ums removed. Now, when participants heard a specific word, they had to register that. They had to push a button. Now, the group listening to the speech with ums present was faster on the button. Why? The ums heightened attention to upcoming words. So when these listeners heard the word they were supposed to listen for, they were faster on that button. Another study indicated that pause as an ums correlate more with truthful than with deceptive speech. The theory being that liars are monitoring their speech more than truth tellers, and this extra monitoring can help reduce the disfluencies. Now, this isn't to say trust the next person who says um, but it does mean that ums are natural, but being natural doesn't mean being preferred. Even though ums may not be caused by nervousness or lack of preparation, people will often assume that they are. And we don't get to give a disclaimer at the beginning of our speech, "Warning: Any ums you hear are there for the audience's benefit". No, we don't get to do that. Ums aren't bad, but they're often seen as bad, so we want to avoid them. So in the next video, we'll talk about how we might reduce ums in our speech.