This chapter explores essential components of speech fluency and how it affects communication and daily interactions. It focuses on key elements of fluency—rate of speech, rhythm, automaticity, and strategic pausing—explaining the interaction of each of these to frame fluent speech. Furthermore, the chapter introduces the speech mechanism, outlining coordination between the respiratory, phonatory, articulatory, resonatory, and neurological systems to produce fluent speech. It stresses the relationship between incoordination among these systems and how it leads to disfluent speech. The chapter discusses the demands and capacities model (DCM) to illustrate the relationship between environmental demands and a child’s speech capacities.