When we engage in interaction, there are numerous ways to formulate a referent, whether through words or behavior. Some recent conversation analytic (CA) studies (eg, Bilmes, 2008, 2009a, 2009b, 2011; Deppermann, 2011a; Hauser, 2011; Stivers, 2007) have demonstrated the tactical nature of members’ word selections and the reflexivity between a particular formulation choice, the local sequential context, and macro-level contexts. This chapter aims to illustrate a practice of formulation done by particular members in two specific types of interaction, namely the practice of prioritization by teachers and interviewers in EFL classroom talk and OPI role-play tasks. The analysis of 38 target cases from a corpus of nine EFL classroom conversations and 71 OPI role-plays indicates that the teachers and the interviewers prioritize actions (such as the acts of questioning, explanation for correction, and repair-initiation) to achieve the institutionally programmed aims of the interaction in the most effective manner. The study concludes with a discussion of the values of prioritization as an analytic lens for understanding the practices of language teaching and testing and as a strategic way of teaching and testing language in and through interaction.