Some podcasts I listen at 3x which feels near my limit of comfort (comprehension drops off at speeds higher than that), but I suspect nearly any normal person can get used to 2x speed. When you are, you can absorb twice as much information in the same amount of time.
(The above applies to talk type podcasts. Music is best at 1x, and dramatizations and such are often best left at 1x to get correct pacing).
* Especially audiobooks generally have only one core idea so even if you miss a part, you're not missing much.
* By listing twice, you will 'revisit' the topic, increasing comprehension.
* Most podcasts/audiobooks actually don't have a lot of new ideas (especially after you've heard a lot of them), so in those cases you're only wasting half the time.
A new screen-reader user would start such an endeavour at normal speed, then gradually increase the speed. It's not much more different to people listening to podcasts and audiobooks at 1.5x speed. The robotic voice is more of a help than a hinderance because of it's consistency.
In college, I had a friend who is blind and her screen reader speed setting was insane. I couldn't understand most of it despite being someone who watches videos and listens to audiobooks at 2x.
Her typing speed was also amazing. I have never seen anyone type that fast before or since.
As you improve, you begin noticing words you already know, and when someone speaks deliberately slow, you can puzzle together sentences.
Eventually, you can understand speech at a normal conversational speed. Most people probably stop at that level, because they don't need more.
But e.g. when watching recorded lectures, I tend to crank up the speed to 1.5x or even 2x until I need to think more about something. The sped-up speech is mostly still quite understandable.
There is no reason to suppose you can't improve your hearing beyond the limits on humans' ability to form coherent thoughts from scratch and move their mouth in the right pattern. Just keep increasing the speed, attune yourself to the artificial voice and then increase it even more until you're at a level that makes untrained people feel like non-native speakers.
I think it's English but the robot voice is geared for Finnish speech patterns.
After listening to the English sample....maybe I'm being naive but is it typical to be able to understand computer speech at that rate? I could barely make out a handful of words and probably wouldn't have believed there was a text to understand in there if the words weren't above it.