Stuttering is a speech problem that interferes with normal word patterns and is not appropriate for a person's age. A person who stutters involuntarily repeats, draws out, does not complete, or skips sounds or words when speaking.

A person who stutters may:

• Repeat sounds, parts of words, and sometimes entire words.
• Pause between words or within a word; sometimes the pauses are silent.
• Substitute simple words for those that are hard to speak.
• Use incomplete phrases.
• Make interjections (such as adding "uh" or "um" in the middle of a sentence).
• Show obvious tension or discomfort while talking. Other physical symptoms may occur, such as eye-blinking or head nodding.
• Make parenthetical remarks. This means a person who is talking seems to abruptly change subject matter. For example, a person may say, "I wonder if it will... where is the dog?"

Stuttering associated with normal speech development is called normal disfluency and usually goes away on its own before puberty. More severe forms of stuttering, called developmental stuttering, usually do not resolve without treatment.