Willingness to communicate (WTC) is an important individual learner difference that can help account for varying rates of language-learning success across individuals. As learner talk is considered to be a key pedagogical activity, instructors and researchers often strive to identify and manipulate key variables that will increase and arouse a learner's WTC and consequently lead to increased levels of learner talk. Conflicting studies have shown varying levels of correlation between ratings of WTC and learner talk. To investigate this phenomenon, this study used idiodynamic methodology to elicit moment-to-moment ratings of individuals' classroom WTC, which were then compared to recorded instances of classroom learner talk. This data was used to answer 2 questions: (a) What is the relationship between situated moment-to-moment ratings of WTC and observable classroom communication? and (b) What factors impinge or enable the realization of learner talk from aroused situated WTC? The results showed little correlation between learner talk and WTC ratings with 4 groups of interrelated factors--(a) motivational forces, (b) listening-related issues, (c) topic-related issues, and (d) language production issues--impacting the WTC-talk relationship. These factors were organized into a hierarchical heuristic model of WTC-talk realization that has both research and pedagogical implications.