How fast can you listen? It depends…

The recent blog post about portmanteaus could have included the ubiquitous “podcast”, a blend of iPod and broadcast, coined in about 2004 to describe digital audio files available to download for listening. You might be less familiar with another portmanteau phenomenon: the “podfasters”. These are people whose time is so precious they elect to listen to their podcasts at extra high speeds. So, how fast can you listen that way? Apps for consuming audio content let you tweak the rate of delivery, offering speeds of 1.5X, 2X or even 3X the standard playback rate. This has created an opportunity for the impatient among us to whizz through their favourite podcasts, packing more content into ever busier lives.

The merits of this approach are hotly disputed. Podfasters undoubtedly feel smug about how much more they are achieving per unit time. Content creators may feel less delighted about someone condensing their carefully crafted audio content and cramming it into their overstimulated brains at maximum speed. From a linguistic perspective, I was interested to find out about the impact of speed-listening on comprehension.

An article at medium.com sheds some light on the potential constraints facing podfasters. Researchers estimate the average rate of speech to be 150 words per minute (for English) and they note that the rate for silent reading can reach 300 words per minute. The author uses these contrasting figures to speculate that there is scope to speed up audio content without any loss in comprehension. Support for this conjecture comes from an article by Raymond Pastore and Albert Ritzhaupt, who analysed the use of time compression to make multimedia learning more efficient. The upshot is that you can understand material delivered at up to 275-300 words per minute, but above that your comprehension falls off dramatically.

Interestingly, although languages vary in terms of speech rates (when measured in syllables per second), a study by researchers at the University of Lyon found that speakers compensate to account for information density. First, researchers calculated the information density for different languages in terms of “bits of information” per syllable. Next, they got native speakers to read comparable passages of text. The slowest speech rates were found for those who spoke more information-dense languages. As one of the researchers put it “there’s this pretty strong push to go for an optimal information rate”.

So how fast can you listen?

If speakers naturally adjust to deliver information at a rate that facilitates comprehension, it makes you wonder what is lost in speed listening. Both scripted podcasts and less formal conversational formats have a rhythm that relies on a particular pace. Rates of speech may ebb and flow, natural pauses help highlight a complex idea being formulated or precede an important piece of information. Humour depends critically on timing. When the audio content is sped up, how many of those cues are diminished or lost? What happens to the art of storytelling when the listener is focused on rushing through as quickly as possible? You may get to the destination faster but was the journey as enjoyable?