Chapter 3 is devoted to the origin, initiation, and modeling of sound change. It begins withtheories of why sound change exists and discusses the teleological and nonteleological approaches. It then connects various models of sound change to these initiation stages. The most pressing question in these models is whether they build on the notion of accumulation of errors, or the involvement of social context such that social interpretation lies at the heart of change initiation. From the micro perspective, the chapter then discusses how change propagates in the individual speaker or listener and how sound change may lead to phonologization as its final stage. It contrasts Neogrammarian sound change with lexical diffusion. It further connects exemplar theories and sound change by extending exemplar knowledge to social meaning. The chapter then addresses the state of the art in /str/-retraction research. It spans the entire linguistic attention to /str/-retraction, from Labov’s early fieldnotes, to Shapiro and Lawrence’s theoretical accounts, to later phonetic and sociolinguistic approaches. Based on the theoretical backdrop provided before and the state of the art in /str/-centered linguistic research, the research hypotheses of the study are then introduced.