Productive peer talk moves have a fundamental role in structuring group discussions and promoting peer interactions. However, there is a lack of comprehensive technical support for developing young learners' skills in using productive peer talk moves. To address this, we designed iTalk-iSee, a participatory visual learning analytical tool that supports students' learning and their use of productive peer talk moves in dialogic collaborative problem-solving (DCPS). This paper discusses aspects of the design of iTalk-iSee, including its underlying theoretical framework, visualization, and the learner agency it affords. Informed by the theory of Bakhtinian dialogism, iTalk-iSee maps productive peer talk moves onto learning goals in DCPS. It applies well-established visualization design principles to connect with students, hold and direct their attention, and enhance their understanding. It also follows a three-step (code [right arrow] visualize [right arrow] reflect) macro-script to strengthen students' agency in analyzing and interpreting their talk. This paper also discusses the progressive modifications of iTalk-iSee and evaluates its usability in a field study. We present the implications of essential design features of iTalk-iSee and the challenges of using it (relating to, for example, teacher guidance, data collection, transcription, and coding). We also provide suggestions and directions for future research.