Why Do We Say 'Hmm' When Thinking?

man thinking
(Image credit: Image via Shutterstock)

Hmm — or sometimes hm or hmmm — ranks among the words we English speakers say the most, and yet we give it scant thought. It's never defined for us as children, is left out of all but the fattest dictionaries and seems barely a word at all. (It doesn't even have a vowel.) Nonetheless, we all manage to grasp hmm's vast range of connotations.

Spoken with a rising intonation: "I didn't understand — say again?"

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Natalie Wolchover

Natalie Wolchover was a staff writer for Live Science from 2010 to 2012 and is currently a senior physics writer and editor for Quanta Magazine. She holds a bachelor's degree in physics from Tufts University and has studied physics at the University of California, Berkeley. Along with the staff of Quanta, Wolchover won the 2022 Pulitzer Prize for explanatory writing for her work on the building of the James Webb Space Telescope. Her work has also appeared in the The Best American Science and Nature Writing and The Best Writing on Mathematics, Nature, The New Yorker and Popular Science. She was the 2016 winner of the  Evert Clark/Seth Payne Award, an annual prize for young science journalists, as well as the winner of the 2017 Science Communication Award for the American Institute of Physics.