Inclusion Criteria (adults who do not stutter):  18-65 years old English as primary language Normal speech, language, hearing, cognition  Exclusion criteria: (adults who do not stutter)  Personal or family history of stuttering Currently taking medication that affects brain function Major medical or psychiatric illness  Inclusion criteria: (adults who stutter)  Aged 18-65 years English as primary language Normal speech, language, hearing, cognition (other than stuttering) Currently stutters  Exclusion criteria: (adults who stutter)  Currently taking medication that affects brain function Speech therapy within the past year Major medical or psychiatric illness  Inclusion criteria: (children who do not stutter)  Aged 6 to 17 years English as primary language Normal speech, language, hearing, cognition  Exclusion criteria: (children who do not stutter)  Personal or family history of stuttering Currently taking medication that affects brain function Major medical or psychiatric illness Language/motor delay  Inclusion criteria: (children who stutter)  Aged 6 to 17 years English as primary language Normal speech, language, hearing, cognition (other than stuttering) Currently stutters  Exclusion criteria: (children who stutter)  Currently taking medication that affects brain function Major medical or psychiatric illness Language/motor delay