Purpose This study measures the experience of spontaneous speech in everyday speaking situations. Spontaneity of speech is a novel concept developed to account for the subjective experience of speaking. Spontaneous speech is characterized by little premeditation and effortless production, and it is enjoyable and meaningful. Attention is not directed on the physical production of speech. Spontaneity is intended to be distinct from fluency so that it can be used to describe both stuttered and fluent speech. This is the first study to attempt to measure the concept of spontaneity of speech. Method The experience sampling method was used with 44 people who stutter. They were surveyed five times a day for 1 week through their cell phones. They reported on their perceived spontaneity, fluency, and speaking context. Results Results indicate that spontaneity and fluency are independent, though correlated, constructs that vary with context. Importantly, an increase in spontaneity significantly decreases the adverse impact of stuttering on people's lives. Fluency did not significantly affect adverse life impact of stuttering. Conclusion Findings support a theoretical construct of spontaneity that is distinct from speech fluency and that can inform our views of stuttering and approaches to stuttering treatment.