Hi everyone. In addition to posting my previous entry in my own LJ, I also posted it to blindpeople. A few minutes ago, a comment was posted there by marta who is on the Live Journal staff. She had the following to say, and I wanted to share for those who aren't part of the community. She says:

"
I wanted to let you know that we've received numerous requests and are now aware of this. The option still exists and you can use it by typing the word "audio" (with no quotation marks) in the captcha box.

Our support team is investigating what is keeping the instructions from being displayed.

Thank you for letting us know about this issue!"

And thank you, Marta, for your response!