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When Reading Speed Deceives You

When creating subtitles, we try our best to keep within the reading speed limit given by the client. The limit depends on the project type and the target audience, but it’s always a specific number — whether it be in words per minute or characters per second. What people often forget, however, is that WPM and CPS are but crude approximations — although practical, they take into account only the text’s volume and not the other attributes that influence the viewer’s pace of reading.

You probably have been in this situation before: a subtitle is well within the limit, but you feel like comprehending it before it disappears is too hard, so you slightly extend the out-time to ensure the viewer’s reading comfort. It does happen occasionally, yet the exact reason why that was necessary can be elusive at times, so I’ve decided to compile a list of cases when the reading speed is deceptive.

1. Complex vocabulary

This one most people know about. Terminology, jargon, slang, exotic names, archaic/literary words, abbreviations, long numbers — they all slow down your reading. Compare these two subtitles:

The subs have exactly the same duration, character count and reading speed, but the latter is harder to go through. So, when the text is tricky, you might want to give it more display time.

2. Tortuous syntax

Sometimes you can’t help but have a long, convoluted sentence spanning multiple subtitles. This can happen when the SDH you’re doing must be verbatim, when such style of speech has significance in the film, or when the dialogue contains text that you can’t really change — e.g. a well-known quote or verse. Subtitles like that are harder to read than the average stuff, so if there are small gaps in-between them, it’s better to close those.

3. Demanding dialogue

Even if a sub doesn’t contain uncommon words or complex syntax, it still can be difficult to absorb in the given time if it has mentally taxing elements — jokes and puns, trains of thought, cultural references, intra- and inter-episodic references, metaphors, etc. These also require consideration when creating timecodes.


Yes, capitalized texts empirically take longer to read, but it seems there is no consensus as to why. Some say it is because they take more horizontal space and hence require more saccades, some insist that it’s due to a reduction in shape contrast between words, and some suggest that the likely cause is unfamiliarity of capitalized words’ contours. But whatever the case, if a subtitle is in all caps, you might want to add to its duration.

5. Poor contrast

This one is also well-known. When the contrast is not there — due to the bright/detailed background, overlap with onscreen text, or lots of motion behind the subtitle — reading the subs can be hard.


Let me demonstrate:

The example is exaggerated, but you get the idea — same duration, same character count, same reading speed, but the second subtitle is tougher.

Now, text contrast is in the eye of the beholder — it will differ from person to person depending on such things as the size, type and color settings of the display, the font and shadow type selected, the amount of screen glare, etc. — but if you suspect that the sub might have low contrast for many viewers, make sure to give it a bit more time.

6. Unexpected position change


A subtitle’s sudden jump to a new position — for example, to the top of the screen — can catch the viewer off guard. These milliseconds of confusion are taken away from the time they have to read the sub, and, to compensate for that, you may want to extend its in-time or out-time a little.

7. Lots of action


This is especially pronounced in movie trailers, recaps and hyper-edited scenes, with their barrage of shot cuts and sound effects. Even if your subtitles have a good reading speed, keeping up with them without missing out on the hectic video sequence can be quite challenging. For instance, try watching this Netflix trailer. It’s subtitled well, considering how rapid it is, but the subs can feel too fast for some viewers. In cases like that, you might want to be more generous with timings when possible, even if it means crossing several shot changes at a time. Or, if that’s not an option, you might have to resort to additional text reduction.

8. Enthralling visuals

On occasion, something in the video will grab your attention so much that it’ll slow down your reading — either by delaying your gaze’s shift to the sub or by forcing you to jump back and forth between the image and the text. This happens most often with visually stunning shots, dramatic moments, explicit scenes and elements crucial to the plot. Watch this short clip, for example (better in full screen):

It won’t work for everyone, but some of you will miss part of the last subtitle due to fixating on the bosom.

So, when the image is particularly eye-catching, you might want to add some frames to the subs.

9. The opposite: punctuation inflation

So far I’ve only mentioned cases when the reading speed value is deceptively low, but the opposite can also happen. The ellipsis, dual-speaker hyphens, double hyphens — they all artificially inflate the reading speed, because they consist of multiple characters but don’t take as much time to process. Here, check this subtitle:

It’s a quick one — whopping 24 cps — but you probably had enough time for it, didn’t you? Well, it’s because of all the punctuation.

And this is it for now. Here’s the takeaway: the reading speed number that your subtitling tool shows you can be misleading; in some cases you need to think beyond it and put yourself into the viewer’s shoes to see whether a sub is too difficult to read in time.

If you know of other cases when the reading speed can be deceiving, please share in a comment below!


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