One thing my lovely Kindle Voyage doesn't do is read out loud. Older Kindle models can read aloud, though, and I keep an old Kindle Touch for just that reason. Because I'm my own production department, I sometimes make edits even after the copy editor has gone over the book. For one thing, some of her question/comments make it clear I need to re-write a sentence or even a paragrah. This means I can introduce new errors,
When I'm getting a book to the page-layout stage, I send a copy of the file to the Kindle Touch and then have the KT read the m.s. aloud to me, while I follow along in InDesign, the page-layout software I use. I find that proofing this way makes it much easier to identify mistakes. On the screen or even on paper, I can read a line like this:
"Yes," she said, "I do plan go with you,"
. . . and totally miss that the word "to" is missing! So long as the missing word is tiny, my brain just fills in whatever is left out. But when I hear that sentence read aloud, the mistake is completely obvious. In addition to errors, sometimes I realize I have used the same word too often, just from hearing it over and over. Whatever the problem, I stop the robot voice, make the correction and then go on.
Another advantage is, I get to hear how someone might pronounce any made-up words. I'm working on a new manuscript, a science fiction romance called Alien Bonds. It's a novel set on an alien world with a lot of made-up names and words. When the robot voice tries to pronounce my invented words, sometimes it's the way I would pronounce it and sometimes it's a little different. Sometimes I like it better, and sometimes I think it sounds totally wrong. But either way, it gives me information.
I assume that the reason the newer Kindles don't read aloud is that not enough Kindle owners were using that feature. It's by no means a substitute for audio books, by the way. The robot voice does not do a great job at inflection and pacing. It will recognize that a sentence ends with a question mark, and infect the proper questioning tone, but it won't pause at all before the next word. It will pause for commas and periods, just not question marks. Go figure! Also, the robot voice has to guess whether to pronounce "read" as "reed or "red" and so on. There are a fair number of heteronyms, like bow (either a weapon or a polite action) which can make for humorous mistakes Sadly, I don't think Amazon will do any work on improving the robot voice. But they might add speakers to future Kindles if audio book sales pick up.
The robot voice is a reasonably fast reader (you can control the pace) but it takes a lot of concentration so I work slowly. I will post a photo of the cover of Alien Bonds soon, as it's almost ready.