I was recently jamming with a friend who is vision impaired and he was playing audio recordings of his lessons where his teacher calls out the changes. As an iReal Pro user, I wondered if there was way I could enable this, and spent a while today playing with accessibility controls on my phone but couldn't get it to work.

A killer feature would be a "call the changes" instrument which maybe a couple of beats before the change says "Eb7 four bars". I found listening to the changes being called was a pretty good way of working too, but this would be awesome as an accessibility feature.