So here is my own experience. I was avid audio book fan for last 3 years and while ago some guy on reddit told me about how he listen books on Audible using high-speed option like 2.x. I never tried that before last summer since at higher speed speech become incomprehensible for me.
What this guy told me is that it's just take time to adjust to it. So I basically started to listen for books at slightly higher speed. Then I gradually increased it and in a few days I could handle 2.0x speed no problem while listening for really complex fantasy (Malazan Book of the Fallen [1]). After two weeks I could handle 2.5x without a problem.
In the beginning it was harder to comprehend at high speed while walking or crossing the street since I lost attention, but in a few months I could do anything while listening without missing any information or emotions of narrator.
To give an example of how far this can go. This spring I was listening for The Expanse audiobook [2] at 4.0x speed. With some effort I could go even faster for like 5.x in case of these particular books, but obviously can not keep up for long.
I still usually listen books at 2.0-3.0x depend on narrator and quality of audio and this skill dont go away even if I have extended time between books like a month or so.
[1] https://www.audible.com/pd/Reapers-Gale-Audiobook/B00M4LRBY6
[2] https://www.audible.co.uk/pd/Abaddons-Gate-Audiobook/B00T6NZ...
UPD: Edit. s/can keep up/can not keep up/
One thing I'd also like to develop / wish was integrated into audible and the like is silence trimming. Some speakers leave outsized pauses in their narration which can be significantly shortened effectively increasing speed with less distortion.
I have the opposite problem where I have trouble paying attention to an audiobook at 1x. I get bored in between words and my mind wanders making it very difficult to keep track of what is being said (as in I hear individual words but have trouble keeping sentences in memory when everything comes too slow)
I wish I had realized this in university and had been able to somehow record and playback lectures at 2x. I always got so little out of lectures because the information wasn't coming in fast enough for me to process correctly.
I don't really use audible, but if you looking for good audio player on Android here is one that can do this:
https://play.google.com/store/apps/details?id=de.ph1b.audiob...