This book takes a new and holistic approach to fluency in English speech and differentiates between productive, perceptive, and nonverbal fluency. The in-depth corpus-based description of productive fluency points out major differences of how fluency is established in native and nonnative speech. It also reveals areas in which even highly advanced learners of English still deviate strongly from the native target norm and in which they have already approximated to it. Based on these findings, selected learners are subjected to native speakers' ratings of seven perceptive fluency variables in order to test which variables are most responsible for a perception of oral proficiency on the sides of the listeners. Finally, language-pedagogical implications derived from these findings for the improvement of fluency in learner language are presented.