I just learned this really cool tech tip about a piece of HTML code that will turn captions on automatically when you embed a closed captioned YouTube video onto a website.
Simply add to the embed code
after the movie URL and inside the quotation marks.
I did this for a short video I made for my job and it really works. A viewer still has the option to turn the captions off, but what I like is that the default setting is for accessibility!
To find out more and see an example, check out YouTube's help page Showing Captions by Default.