Assessing the state of the art in longitudinal L2 pronunciation research

Abstract Longitudinal research methods often call to mind studies of various lengths. However, longitudinal research involves complex decisions related to study length, number of sessions, and session spacing, and these longitudinal choices must be coordinated with other aspects of research methodology. In this synthesis, I analyze 39 longitudinal L2 pronunciation studies that were published between 2006 and 2021 and did not include a pronunciation-specific intervention. I examine longitudinal design choices in light of participant sample characteristics such as age and context of learning, and measurement framework characteristics, which include choices related to target structures and tasks. Among other findings, results point to a lack of longer-term, multiwave studies dealing with pronunciation development. I offer suggestions for future work that can enhance the scope of L2 pronunciation research as well as recommendations for conducting and reporting longitudinal research.