Ditch these 10 common crutch phrases, says Stanford expert—they ‘undermine our competence and intelligence'

You probably use the occasional crutch word or phrase without realizing it. Most people do.

But beware, says Stanford University communication expert Matt Abrahams: They can get you into trouble, by negatively impacting the way other people see you. Crutch phrases often include "hedging language" that water down your sentences and make you seem less smart, he says.

"[They] can actually undermine our competence and intelligence," Abrahams, a communication consultant and organizational behavior lecturer at the Stanford Graduate School of Business, tells CNBC Make It.

Here are 10 hedging phrases Abrahams says people should steer clear from, especially in professional settings:

1. "I think"
2. "Sort of"
3. "Kind of"
4. "It seems"
5. "Perhaps"
6. "It might be"
7. "It looks like"
8. "Possibly"
9. "Maybe"
10. "I feel like"

Instead, opt for "declarative statements," says Abrahams.

Say your boss asks you to take on a big project, for example. Responding, "I think I can pull it off," can make you sound like you lack confidence —  especially in comparison to a more confident "Yes, I'd be happy to take it."

Even more simply, you can swap "I think" out for "I know" or "I believe," Abrahams says: "If I say, 'I kind of think we should do this,' it's very different from, 'We should do this.' And [the latter] sounds more confident and strong."

If you really want to sound competent — particularly when someone is explaining a complex topic or subject to you — you can repeat what they said back to them, or ask them a question.

"Saying something like, 'So what I hear you saying is,' demonstrates that you've actually really listened to the person. It demonstrates understanding and builds your confidence in the eyes of other people," Abrahams says.

A 2015 study series from Harvard and Wharton researchers backs him up. Students were asked to solve a brain teaser with a partner, and given three options for communication: asking for advice, telling their partner, "I hope you did well," or saying nothing at all. Those who asked questions were viewed as more intelligent than those who didn't, the studies found.

"By showing that I've taken the time to listen to you [and ask questions], that makes you think, 'Well, he's smart enough to understand what I'm saying," says Abrahams.

Want to make extra money outside of your day job? Sign up for CNBC's new online course How to Earn Passive Income Online to learn about common passive income streams, tips to get started and real-life success stories. Register today and save 50% with discount code EARLYBIRD.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life.