See some helpful tips to improve your own communication to those hard of hearing
Ensure that subtitles/captions are cut down to and presented at an appropriate words-per-minute for the target age-group.
Provide signing Consider incorporating sign language interpretation into training materials to accommodate learners who are deaf or hard of hearing and rely on sign language as their primary mode of communication.
Use symbol-based chat.
Why people with hearing disabilities don’t disclose
Deaf/deaf/Hard of Hearing