The purpose of this study was to investigate the various roles that early elementary teachers adopt when questioning, to scaffold dialogic interaction and students' cognitive responses for argumentative practices over time. Teacher questioning is a pivotal contributing factor that shapes the role teachers play in promoting dialogic interaction in argumentative practice and that different roles serve different functions for promoting students' conceptual understanding. The multiple-case study was designed as a follow-up study after a 4-year professional development program that emphasized an argument-based inquiry approach. Data sources included 30 lessons focusing on whole class discussion from three early elementary teachers' classes. Data were analyzed through two approaches: (1) constant comparative method and (2) enumerative approach. This study conceptualized four critical roles of teacher questioning--dispenser, moderator, coach, and participant--in light of the ownership of ideas and activities. The findings revealed two salient changes in teachers' use of questions and the relationships between teachers' question-asking and students' cognitive responses: (1) teachers increasingly used multiple roles in establishing argumentative discourse as they persistently implemented an argument-based inquiry approach, and (2) as teachers used multiple roles in establishing patterns of questioning and framing classroom interactions, higher levels of student cognitive responses were promoted. This study suggests that an essential component of teacher professional development should include the study of the various roles that teachers can play when questioning for establishing dialogic interaction in argumentation and that this development should consist of ongoing training with systematic support.