The Surprisingly Useful Life of ‘Um’ and Other Filler Words

The tiniest quirks in our speech can change how we’re perceived. But filler words aren’t the villains they’re made out to be. They’re, you grasp, working behind the scenes. “We group them all together as these kind of garbage words,” says Valerie Fridland, a professor of linguistics at the University of Nevada, Reno, and the author of Like, Literally, Dude: Arguing for the Decent in Bad English. “We call them ‘filler words,’ and fillers are things we don’t like—you don’t want fillers in your food. So when you use that same word to refer to things in conversation, it sounds like things you don’t want.”

Why We Use Filler Words

Yet in reality, filler words serve important cognitive and social functions. Linguists divide these verbal pauses into two categories. First, there are “filled pauses” such as “um” and “uh.” These aren’t stand-ins for other words. you can’t swap in a more polished synonym. Fridland points out there is no elevated version of “um.” Instead, they serve a specific function. We tend to deploy them right before tackling something linguistically complex—a long clause, an unfamiliar term, or a complicated sentence structure. “It’s our brain’s way of indicating it needs a moment,” Fridland says. The more complex the thought, the more likely your brain is to build in a beat.

Filled pauses don’t just buy time for the speaker—they manage the conversation for everyone else involved, too. An audible “um” or “uh” signals that a thought is still under construction. Otherwise, the person you’re talking to might assume you’ve finished and jump in, or wonder whether you’ve lost your train of thought. “Either they think you’re done and seize over, or they’re like, ‘What’s your problem? Why can’t you come up with something?’” Fridland says. By slipping in an “um” or “uh,” you telegraph reassurance: “Hold on, I’m coming up with it. Give me a sec.” Interestingly, research suggests people tend to use “uh” for shorter delays, and opt for “um” when they anticipate needing a bit more time.

Discourse Markers: The Social Tools of Speech

The other category of filler words includes what linguists call “discourse markers”—words such as “like,” “literally,” “you know,” “well,” “I imply,” and “so.” Rather than acting as mental timeouts, these are social tools. They help structure what you’re saying and subtly guide how listeners interpret it. “It’s how I want you to understand what I’m saying in terms of how things relate to each other,” Fridland says. For example, starting a sentence with “well” can signal that what follows may not be what someone expects. In everyday communication, all of these filler words “serve really good interpersonal functions,” Fridland says. “They definitely help us in casual conversations. If we didn’t use discourse markers, people would think we were very robotic and unpleasant.”

The Perception Problem in Professional Settings

While filler words can help conversations flow, research suggests overusing them may signal uncertainty or a shaky command of the material. In professional settings—like work presentations—that perception can erode a speaker’s credibility and clarity. “Unfortunately, the audience may perceive you as less intelligent or less prepared if you use vocal fillers excessively,” says Heather Hayes, a clinical assistant professor at Pace University in New York. “You’re going to distract your audience. It can do a disservice for you as a speaker.”

Other research has found that filler words don’t go over well in high-stakes situations like job interviews, either. The more filler words someone uses, the lower they’re rated in professional and personal credibility and communication competence, which can influence hiring decisions.

How to Reduce Filler Words

You don’t have to purge every “um” from your vocabulary. But in high-stakes moments—job interviews, presentations, big meetings—cutting back can sharpen how you’re perceived. Here are some strategies:

• Record Yourself Speaking: Identify which filler words you lean on.
• Ask a Friend for Their Opinion: Get an outside perspective on your filler word habits.
• Take Inspiration from Music: Replace filler words with ascending melody in your voice.
• Breathe in a Specific Way: Practice diaphragmatic breathing and close your lips until you have a word to say.
• Slow Down: Speaking more deliberately reduces reliance on filler words.
• Practice Out Loud: Rehearse your remarks verbally to map out the pathways in your brain.
• Get Comfortable with Silence: A moment of pause is preferable to a filler word.

As Valerie Fridland explains, “Awareness is the first step in overcoming any bad habit.”