I am hearing-impaired and would like to know if transcripts of the Crash Course are available.

Yes, transcripts of the Crash Course are available on each individual
chapter page below the video box.  We hope to eventually be able to
offer a subtitled or closed--captioned version of the Crash Course as
well.  If you have skills in this area and are interested in helping us
to make this happen, please contact us.  Thank you.