A fluency disorder occurs when:

A fluency disorder is characterized by interruptions in the flow of speech, which often manifest as repetitions, prolongations, or pauses that disrupt the natural rhythm of talking. When speech is produced with high effort, it signifies that the speaker is experiencing difficulty in maintaining a smooth, effortless flow. This heightened effort can reflect the speaker's struggle to get words out fluently, which is a hallmark of fluency disorders like stuttering.

In contrast, while pronunciation may be altered or modified in various speech disorders, it specifically pertains to how sounds are produced rather than the fluency of speech. Furthermore, while disfluencies can be observed in all speakers to some degree – such as in normal speech patterns where hesitations occur – fluency disorders are distinguished by their severity and impact on communication. Lastly, though speech can be fast and disjointed in some fluent types of speech, it does not accurately align with the fundamental characteristics of a fluency disorder, which primarily deals with the flow and smoothness of speech rather than just its speed or coherence.