Calibration between judged and actual performance related to cognitive certitude is known as "cognitive certitude of calibration" (CCC). CCC is an essential factor that can affect an individual's calibration behavior related to his/her learning effectiveness mediated by cognitive and affective factors, such as cognitive anxiety, learning interest, and self-efficacy. Thus, the aim of this study was to examine learners' cognitive certitude of calibration and its correlation to cognitive anxiety, online learning interest, and learning self-efficacy. The participants were 4th grade students of Southeast Asian heritage who were learning Chinese as an L2. The participants practiced Traditional Chinese Pinyin via a website called "Quickgame," which embedded a series of drills and practices. Time series analysis and correlation analysis were used to test the interplay between online learning interest, learning self-efficacy, cognitive anxiety, and CCC. The results of the time series analysis showed that as practice times increased, the students' CCC improved, and CCC increased as practice times increased. The results of this study imply that by practicing calibration, participants' cognitive and affective factors can be improved when learning Traditional Chinese Pinyin.