AbstractDrawing on data from a learner corpus of blogs, this study explores epistemic expressions used in Chinese heritage language (CHL) writing from a developmental perspective, and aims to provide a better understanding of pragmatic development in heritage language learning context. A total of 6,511 blog entries written by 266 heritage learners from four different proficiency levels were analyzed cross-sectionally. The findings revealed three notable developmental patterns in CHL learners’ use of epistemic markers (EMs): 1) a rapid increase in the frequency and diversity of EMs at the beginning of CHL curriculum, 2) a period of stability from the second quarter onward, and 3) a divergence of frequency and diversity at the advanced level, whereby the diversity of EMs increased again, but the overall frequency of EMs remained unchanged. Significant developmental variability was also found between grammatical sub-groups of epistemic markers. Overall, the study shed light on the development of CHL learners’ pragmatic competence, and demonstrated the effectiveness of learner corpora as a research tool for studies of pragmatics learning.