I went through both lessons 1 and 2 without knowing there was audio. Do the instructions say make sure your audio output isn't muted?
However, both lessons had essentially the same wording in audio as in text on the page, so I went through them both successfully. Then came Lesson 3 and suddenly there was no data, until I figured it out and turned the sound on.

Can't stand my computer talking to me. It's as bad as robot phone calls-- "Police say crime is up in your area. Press 1 if you want JustForSuckers Alarm System installed. If you are among the first fifty to respond, you will get--" you know the kind of thing.

There are different learning styles, and listening to somebody talk is not mine; nor has it ever been. This isn't something that has scarily developed lately.

Audio raises privacy issues, too.

i had to abandon the lesson 1 because of this. The computer I use for research is not connected to speakers. I did not see a transcript. hmmm...

Is there a way to take the lesson again on another computer?