To stutter means to speak with involuntary pauses or repetitions of sounds, especially at the beginning of words. Someone who stutters might say “I w-w-want to go outside” or get stuck on the first sound: “I'm going to the p... p... park.” It's a speech pattern the person can't easily control, even though they know exactly what they want to say.

Stuttering is different from pausing to think of the right word or being nervous. A person who stutters knows the words, but their mouth and brain temporarily struggle to coordinate the smooth flow of speech. Some famous people who stuttered include President Joe Biden and actor James Earl Jones, who became the voice of Darth Vader. Many people who stutter learn techniques to speak more fluently, though the condition may never disappear completely.

The word can also describe machines or movements that start and stop jerkily. An old car engine might stutter when it's having trouble, or a video might stutter when the internet connection is weak.