I have removed a seldom-used feature and replaced it with something I think is much more useful.
Before, when you clicked on the bullhorn in the upper left-hand corner, the card was read aloud by a robotic voice. This voice was annoying and hard to turn off.
Now, when you click on the bullhorn, the horn will turn white to indicate that the card has not yet been read. Why would you want to do such a thing?
Suppose this is a massive card and you don't feel like reading it all at once. Or suppose you wish to reply to this card but you want to read the other cards first. By clicking off the bullhorn indicator, this card will appear in the index as unread (no diamond). After you've finished reading through the rest of the volume, you can just glance at the index to be reminded which cards require further attention.
[Incidentally, you must click ON the bullhorn itself, not just within the button rectangle.]
So the most efficient way to tackle a voice volume is to first read the Preface, then cycle through all the other hello cards, and then return to the index, flip on Speed Reading Mode, and plow through the remaining cards from beginning to end. Whenever you find a card you want to come back to, just click on the bullhorn.
Later, if speed reading mode is still in effect, you can just click on the forward arrow in the index card and the button will automatically scan until it finds each of your "come-back-to" cards.