Complex Dynamic Systems Theory (CDST) has been applied to the study of second language acquisition to possibly account for the nonlinear development and variability found within second language development. Characteristics of a dynamic system that make it compatible with examining the developmental trajectory of second language acquisition include the presence of subsystems, variability, and the dependence on internal cognitive and external social and environmental resources (De Bot, Lowie, & Verspoor, 2007; Van Geert, 2008). Using a CDST perspective, this study looked at the use of the preposition in within the written communication of a native speaker of English and a non-native speaker. Three methods of data analysis-target-like use analysis, form-function analysis, and metaphor analysis-were employed to track how the use and function of the preposition in varied over time. Results indicate that an individual’s literal and conceptual engagement with and production of a language develops over time in a non-linear manner.