Speech Speed vs. Understanding What Was Said

by Neil Bauman, Ph.D.

A man wrote,

Have you addressed the issue of “speech rate” as a factor in hearing loss and comprehension?

As I recall, the “optimal” speech rate is approximately 180 words per minute (wpm). Yet I find that the broadcast industry (radio and TV) are hiring commentators who speak at least 210 – 230 wpm. (Unfortunately I do not have access to the recording technology which would provide more definitive data.) This rapid rate is virtually unintelligible to any one with a significant hearing loss. And, as you know, this includes a large proportion of older people (65+), myself included!

The nightly MSNBC Television show is a good example—from very fast to perfect speed!

I’m interested in your knowledge and opinion on this trend. I am on a one man crusade to encourage the broadcast industry to “slow down” so we older folks, many with a hearing loss, can understand what they are saying!

My hat is off to you. I hope your crusade makes a difference. It will help countless millions of people.

You are so right that when people speak too fast, we often miss a lot. There are a number of reasons why. Let’s look at some of these.

1.  How fast our brains can process speech

If we have good hearing and a person is speaking at a moderate speed, our ears will pick up and our brains will process what we are hearing in real time, AND we will still have time to think about what we have heard. In other words, we will understand and assimilate the message.

However, as a person speaks faster and faster, we spend more and more of our time trying to “catch” the words spoken, and thus we have less and less time left over to try to assimilate what we have heard. This is where we begin to lose it. We know the person is talking, and often we know the general subject, but we miss the point he is making. And remember, this is in adults with both normal hearing and normal cognitive function.

The truth is, not all people are adults in their prime. More and more are becoming seniors. As we get older, we slow down. That is no secret. So it should be no surprise that our brains also slow down. As a result, it now takes longer for us to process speech. It also takes longer for us to assimilate what we have heard. Therefore, seniors are at a disadvantage, even when listening to a speaker who is speaking at a normal rate.

As the speech rate picks up, we seniors are at an even greater disadvantage. The result is that the faster a person speaks, the more we miss until listening to a speaker is largely a waste of time. That is why so many seniors tune out. It is all flying “over our heads” so to speak.

The same holds true for children who are just learning the language and need time to figure out “hard” words. This slows down their processing speed. It also holds true for people for whom English is not their first language. They need time to “retranslate” what was said. Furthermore, some people are not as cognitively fast as others, and thus need more time to process what they hear.

The above groups include a large percentage of the population. And note that so far, we haven’t even considered people with hearing loss.

Numbers of people with hearing loss fit into all the above categories to be sure. However, our hearing losses just compound our difficulty in understanding others. But even if a hard of hearing person is in the prime of adulthood and everything is working normally except that they don’t hear well, they still have problems.

You see, our “broken” ears miss words and parts of words (phonemes). Therefore, the information our ears send to our brains is full of holes and gaps. Think of a puzzle that has lots of pieces missing so you can’t recognize exactly what the picture is about. That is an analogy to what we hard of hearing people hear and understand.

Our brains have to work overtime to try to figure out the missing parts. We use what we already know of the subject, what we know of the structure of the language, what we can speechread, what we deduce from body language, etc. to try to make sense of what we heard. All this takes time. And by the time we have this figured out, we’ve missed the next few words so there are even more gaps to try to fill in.

Obviously, we need a person to speak more slowly to give our brains a chance to keep up. Speaking slowly with lots of pauses really helps us in this regard.

Not only do our brains need to try to figure out what we heard, they also need to try to reconcile what our ears heard with what our eyes saw (speechread). And this gives rise to some unexpected problems. You see, in English, lip movements only correspond to speech sounds about a third of the time. The rest of the time what we see and what we hear don’t have any direct correlation. Therefore, we can hear one word, and yet at the same time “see” an entirely different word on the speaker’s mouth.

Now we have a problem. Which do we believe—what our faulty ears thought they heard, or what our eyes thought they saw? For example, suppose we thought we heard the word “white”, but we saw the word “queen” on the person’s lips. Which was correct? You see, unfortunately for us, the words “queen” and “white” look identical on a speaker’s lips.

(Note: words that look the same on a person’s lips but sound differently are called homophenes. Don’t confuse homophenes with homonyms. Homonyms are words that sound the same but have different spellings such as “their—there” or “bear— bare”. Incidentally, all homonyms are also homophenes.)

Now, back to the words “queen” and “white”—maybe the context lets us know it had to be a color, so our brain puts in “white” and not “queen”. This mental gymnastics takes time.

Sometimes the choice is not so easy as there may be a number of words we need to substitute to try to find the right one. For example, the following words all look identical on a person’s lips—chews, jute, shoes, June, shoot, juice, choose and Jews. It can take our brains considerable time to figure out the right word—especially if the word is the one that sets the real meaning of the context. And this assumes we only have one word that is ambiguous. If there are two or more homophenes, the problem expands exponentially. Think of the above words and try to make sense of this sentence if you only see the words on the speaker’s lips. How long, if ever, will it take you to get it right? Here’s the sentence—”If he chews jute, will the juice fall on his shoes?”

Depending on your mindset at the time, you might see, “If he June June, will the June fall on his June? Or if it is during the fall hunting season, your brain might lock onto the word “shoot” and you’d see, “If he shoot shoot, will the shoot fall on his shoot?” How long would it take you to substitute word after word until you got the right message? Probably never. Yet that’s what we deal with day after day.

This is why we so desperately need people to speak slowly and clearly and pause from time to time. Our brains need time to “catch up” and also “catch their breath” so to speak.

By now it should be obvious that when a person talks faster than normal, hard of hearing people, seniors and many others lose much of what is said. This is why radio announcers, in particular, need to slow down their speaking rate. When they speak fast, we miss their important information.

Let me give you two examples that I have noticed when listening to my car radio while driving.

Announcers speak particularly fast when reading advertisements. Speaking fast is thought to increase the excitement of the ad and thus motivate people to buy the product. However, I wonder if the “bright lights” in the radio/TV and advertising industries have ever stopped to think that when they rattle their ads off so fast, a large proportion of the population miss key words in their aids. The result is that their message is just not processed properly by many seniors and hard of hearing people so they do NOT buy their products. This means they waste a considerable portion of their advertising dollars—not exactly a bright decision on their part.

Our local radio station has a “TrafAx” (traffic accident) report so you can avoid accident sites and the consequent traffic congestion in your area. However, when the announcers give this report they immediately increase their speaking rate and rattle off the locations so fast that I’m not able to determine the locations they are talking about—so this piece of newsworthy information is useless to me (and to all the others in the same boat).

This not only applies to radio/TV announcers, but to presenters and speakers at conferences and other places. For example, in addition to speaking fast for the “excitement” effect, sometimes presenters talk faster (and faster) as they see they are running out of time and want to finish their speech. When they do this, we “lose it” and have to put up our hands and ask them to repeat it as we missed some important point. The result is that they are now even more pressed for time and rattle on faster and faster, and we need to interrupt them time and again (or totally miss everything).

There was a book that came out some years ago with a long title that basically said it all. It went something like this, “If You Don’t Have Time to Do It Right the First Time, When Will You Ever Have the Time to Do it Over Again?”

Therefore, it is much better to speak slowly and clearly the first time and cover the essentials and let everyone catch your points, than to speed through your presentation and leave half your audience in your dust. Think about this and remember to slow down!

2.  How fast our eyes can detect speech movements in order to speechread.

Many of us (hard of hearing people) speechread to try to make sense of what our faulty ears hear, and to fill in the gaps in what their ears totally miss. This makes speechreading critical to understanding what a person is saying.

In order to speechread, you first have to see the lip (and facial) movements the speaker is making.

Here is something I’ll bet few people have considered. Our eyes don’t have the ability to detect an unlimited number of movements per second. That is why films are set to run at 30 frames per second. At that point they appear to us to be flicker-free because our eyes can’t detect more than that number of movements per second.

In fact, our eyes can’t even process that many movements when it comes to UNDERSTANDING what we are seeing. And if our eyes can’t “grab” it, our brains certainly can’t process it.

For example, when a person talks at a normal rate, they make between 13 and 15 speech movements per second. Even that is too many movements per second for our eyes to accurately “grab”. In fact, our eyes can only pick up around 8 or 9 of these speech movements per second. This means if people are talking at a normal rate of speed, we miss between one quarter and one half of what they say just because our eyes can’t keep up.

That is not all, our brains also have to process what our eyes see. As we get older, our brains slow down as we have already seen, so it takes longer to process the signals our eyes send to our brains.

Therefore, it really helps if the person speaks slower and leaves pauses to give our brains a chance to catch up. So, slow down!

3. How fast we can read the captions.

I don’t watch any TV unless it is captioned. That is how important captioning is to my understanding a person talking. Unfortunately, the faster a person speaks, the faster the captions fly off the screen. Thus, if you are not a fast reader, the words fly off the screen before you get a chance to read them. As a result, you miss some, or much, of the dialogue.

Another aspect of captioning that few realize is that if a person speaks too fast, the captioner condenses what the person says to keep the captioning down to a reasonable speed so it doesn’t fly off the screen too fast.

This is great in order to try to caption a rapid speaker’s words, but it is no longer verbatim like it should be. And this causes more problems. You see, we typically both speechread the actors and read the captions at the same time. (Actually, we rapidly switch from one to the other and back again.) Problems arise when we see a person’s lips say one thing and the captions say something different. At that point we get confused. Now it takes even more time to figure out what was said. Thus, we get further and further behind.

The solution is simple. If people speak at a moderate speed, captioners will have enough time to caption everything verbatim, the words will not scroll up too fast, and we will have time both to read them and comprehend what was said.

Not only is speaking at a moderate pace important for elderly people, and for hard of hearing people, but it is also important for people who are not fast readers such as children, people with poor eyesight, people who have not had a lot of education and people for whom English is not their first language.

When you consider all these groups, the majority of the population fits into one or more of these categories. Therefore, unless public speakers (radio and TV announcers, actors, presenters, etc.) talk more slowly, most people watching their programs will miss part or most of what was said.

Some wag once wrote, “There are three kinds of people in this world—those that make things happen, those that watch things happen, and those that wonder what happened.”

When people speak too fast, so many of us are left in the dust wondering what happened! Yet the answer is so simple. Just “slow down”!