Main take-aways:
Do not speak too slowly. Watch your intonation so that you sound authoritative. Use informal and friendly language (I, you, we) and stay away from academic language. Don't use machine-read audio. Use your own examples and let your personality come through. Create a connection with your learners.
References:
Moreno, R., & Mayer, R. E. (2000). A Coherence Effect in Multimedia Learning: The Case for Minimizing Irrelevant Sounds in the Design of Multimedia Instructional Messages. Journal of Educational Psychology, 92(1), 117–125. https://doi.org/10.1037/0022
Simonds, B. K., Meyer, K. R., Quinlan, M. M., & Hunt, S. K. (2006). Effects of instructor speech rate on student affective learning, recall, and perceptions of nonverbal immediacy, credibility, and clarity. Communication Research Reports, 23(3), 187–197. https://doi.org/10.1080/08824090600796401
