>But, he says, instead of being limited by how quickly we can process information by listening, we’re likely limited by how quickly we can gather our thoughts. That’s because, he says, the average person can listen to audio recordings sped up to about 120%—and still have no problems with comprehension.
The deduction that is quoted does not follow: speeding up audio recordings with 120% results pressing both the auditory system as the language and thought systems (or any other potential bottleneck) to be sped up proportionally since it's a pipeline.
Similarily the posted article (I have yet to read the original one) states in the title that "human speech" has a universal transmission rate, but the research tested reading not speech, so this may or may not be true.
Perhaps the bottleneck is human speech, with the side effect that listening is never trained beyond the typical speech rate limit. (in this case the higher speed syllable languages would be easier to pronounce fast, and the lower speed ones harder to pronounce fast)
Perhaps the bottleneck was in the visual burden of reading, a language that encodes more bits per syllable implies more types of syllables, which irrespective of size or number of characters puts a classification demand on the visual system (classifying a symbol coming from a set of only 2 symbols will be easier, but will require more classification instances than classifying from a large set of characters but with fewer classification instances).
Perhaps the bottleneck was again in speech during reading by subconscious vocalizing of the text.
Perhaps the bottleneck was in the auditory "speech to syllable" classification.
Perhaps the bottleneck was in parsing text.
Perhaps the bottleneck was in "accessing thoughts" etc.
So it is rather hard to identify where the bottleneck is located without having a means of detecting where in the brain the "incoming queue is full" vs "incoming queue is waiting" during speaking, listening, reading. And which of these 3 causes this universal bottleneck (since I gave 2 examples of how an apparent bottleneck in reading could stem from not being trained beyond a possible universal bottleneck in speaking rate...)