Pedagogical Conversational Agents (PCAs) are increasingly used to provide personalized support in digital learning. This study examines how different levels of learner control that a virtual teaching assistant (TA) offered impact students' self-efficacy, learning effectiveness, and satisfaction, given the moderating effects of student characteristics. A between-subjects study with 215 students across three learner control conditions revealed that the moderate control (i.e., Assisted Inquiry) led to higher perceived learning effectiveness than the high control. Agreeableness, Extraversion, and Openness were found to significantly influence students' learning. These findings underscore the need for adaptive PCA systems that tailor instructional support with scaffolding and balanced learning interventions while accounting for learners' personality traits to enhance student engagement and perceived learning effectiveness.

Video-sharing platforms such as TikTok have offered new opportunities for d/Deaf and hard-of-hearing (DHH) people to create public-facing content using sign language – an integral part of DHH culture. Besides sign language, DHH creators deal with a variety of modalities when creating videos, such as captions and audio. However, hardly any work has comprehensively addressed DHH creators’ multimodal practices with the lay public’s reactions taken into account. In this paper, we systematically analyzed 308 DHH-authored TikTok videos using a mixed-methods approach, focusing on DHH TikTokers’ content, practices, pitfalls, and viewer engagement. Our findings highlight that while voice features such as synchronous voices are scant and challenging for DHH TikTokers, they may help promote viewer engagement. Other empirical findings, including the distributions of topics, practices, pitfalls, and their correlations with viewer engagement, further lead to actionable suggestions for DHH TikTokers and video-sharing platforms.