Speed ratings that match what you hear (speaking speed and pauses)

Ever picked a slow video and found the speaker racing through every sentence, or skipped a "fast" one from a teacher who pauses after every phrase? Every video gets a speech score that estimates how much work your ears and brain have to do to keep up. It draws on research into listening in a second language and looks at three things: how fast people talk, how many words they say before they pause (the mean length of run), and how much the words run together. Short pauses between phrases give you time to process what you just heard, so they count in a video's favour. Long stretches where nobody talks, like music or someone showing something on screen, don't make a video easier or harder, so they're left out.

The score always looked at pauses, but it treated every silence the same. Learners told us some videos felt much faster or slower than their rating, and we saw it in how people watched: one teacher known for speaking slowly came out as one of the fastest on a channel list we put together, because that list counted speed without any pauses at all. So the score tells helpful pauses apart from empty stretches, and every change is checked against the videos learners mark as too fast or too hard.