  Benefits of learning by teaching (LbT) have been highlighted by previous
studies from a pedagogical lens, as well as through computer-supported systems.
However, the challenges that university students face in technology-mediated
LbT$\unicode{x2013}$whether it be teaching oneself, teaching a peer, or
teaching an agent$\unicode{x2013}$are not well understood. Furthermore, there
is a gap in knowledge on the challenges that students encounter throughout the
process of teaching (content selection, preparation, teaching, receiving and
giving feedback, and reflection) despite its importance to the design of LbT
platforms. Thus, we conducted a study with 24 university students where they
taught content they had not fully grasped, without guidance, and participated
in a semi-structured interview. Results demonstrate that participants
encountered the following challenges: psychological barriers relating to self
and others, and lack of know-how. Furthermore, we illuminate design
implications required to overcome these challenges and benefit from LbT without
requiring prior training in pedagogy.
