Monday, January 31, 2011

Stuttering constant across cultures?

 An interesting comment by a reader on the prevalence of stuttering across cultures.
This subject is very interesting, as big part of speech pathologists believe that stuttering rate is the same everywhere, and only a minor part believe that there are substantial differences in the rate of stuttering in different populations. Those who believe the rate is same everywhere, unfortunately, are not interested in cross-cultural studies. After asking people from different cultural background for many years about stuttering, I found that the differences in the incidence are absolutely huge. For example, you will find that a huge number of people from sub-Saharan populations had a stuttering problems (many have it as adults as well). On the other hand, you can hardly find a stuttering individual among the Chinese, or among Native Americans. Unfortunately, most of the "serious" speech pathologists are not interested to examine these cultural differences, instead they try to explain the published data on the existing differences by different methodologies used by different speech pathologists in different populations. But how come that experts, almost educated in Western Universities, always make the same "mistakes": they exaggerate the number of stutterers in sub-Saharan Africa (and African Americans), and grossly underestimate the number of stutterers among American Indians and Chinese populations. Fearing to face facts has never helped anyone in finding the real causes of any phenomena. I very much hope that many professional speech pathologists will read this blog and comment from their own experience on this topic.
In the past, I wrote that stuttering is relatively constant across cultures. I am not so sure any more. For following reasons:
(a) Stuttering is driven by genetic mutations. Different ethnic groups have different mutations in their gene pool. So some could have more or less of these mutations.

(b) Stuttering might not occur due to certain genes, which again might differ in different gene pools.

I am not surprised that a difference between Sub-Saharan and other groups exists. The latest research on Neanderthal DNA has shown that Sub-Saharan groups do not have any Neanderthal genes. Only those groups getting out of Africa have Neanderthal genes. Moreover, those groups were very likely under severe evolutionary pressures to adapt to different habitats. Speech might have been a critical feature, and mutations have been selected out.

I haven't looked yet at empirical studies, but I would be surprised if such research exists and is water tight.

I revise my statement:

(a) Stuttering exists in all cultures.

(b) Prevalence might vary.

Here is also an older post on the topic.

12 comments:

JD said...

what about language and cultural differences?

Can you explain how language differences or social cultural factors (higher birth rate in third world countries) might influence prevalence of stuttering?

sachin said...

Very interesting. I read something similar about the spread of certain genes which offer immunity to Malaria, but causes Sickle cell Anemia- from Africa to Asia etc.
Only shows how little we know about stammering- and how important it is to have an open and humble attitude...
Thanks..

Anonymous said...

You mentioned this before here

http://thestutteringbrain.blogspot.com/2010/12/book-on-choral-singing-and-stuttering.html

Tom Weidig said...

@JD: We know that stuttering is not just driven by genes, but also by developmental issues.

It's clear that those kids who grow up in deprived environments do not grow to their full potential. This might well tip the balance and lead to more stuttering. This phenomena should probably be similar for other brain disorders.

JJ said...

I'm Chinese and I grew up in the States.

When I was a 6 (back in the 80s) my parents did take me to a psychologist to see about my stuttering.

And he suggested that I stuttered because I was learning 3 languages at the same time (English, Mandarin, and Taiwanese) and that my parents should just emphasize one language at home.

Hmmm... well, let's just say I still stutter and now my other 2 language skills aren't as fluent as English.

Still, it's strange because I'm the only one in my entire extended family that stutters and also the only one that grew up outside of Taiwan.

JJ said...

One thing I would like to add is that I can become completely fluent if I mix and match the way I talk.

So if I'm speaking to someone who also understands both English and Mandarin, then I can switch words in a different language when I get stuck.

Of course overall I do tend to block on words that sound similar, e.g. hard consonant words, in all 3 languages.

(Though I stutter a lot less in Taiwanese, my weakest language).

Tom Weidig said...

@JJ: Good strategy mixing languages. I used to do that, too!

Ora said...

Your reader wrote "After asking people from different cultural background for many years about stuttering, I found that the differences in the incidence are absolutely huge."

This method (asking people) is not likely to get reliable estimates of the incidence of stuttering. There are lots of reasons why you might get different answers. Here are a few:

- Stuttering is perceived and defined differently in different cultures. Someone who's considered a stutterer in one culture might be considered merely a less fluent speaker in another.

- There may be difference in the acceptability of stuttering. In a society where stuttering is embarrassing or shameful, people will hide their stuttering and speak less, so that people will hear less stuttering and believe that its prevalence is lower.

- Differences in treatment rates in different societies will presumably result in less stuttering in the treated populations.

- Etc., etc.

I don't mean to suggest that personal observations are without value. But I would be very cautious about accepting conclusions based on asking questions - even asking a lot of questions - without controlled studies and hard science to back it up.

Anonymous said...

I am not CHinese, but I have met Chinese people who have told me that "there are no Chinese people who stutter". Strange because I am a member of a self-help group and there is actually a high percentage of Chinese people in the group who stutter. I think attitudes of a culture would force a lot of stutterers to remain "covert" and avoiding interaction to an extent that they would not be seen as stutterers.

Anonymous said...

I am from India. I know one elder person who knows two languages english and tamil. He says he is 100 % fluent while speaking in tamil but he stuck when he starts speaking in english particularly more with strangers.
I have also observed one thing. I am from the part of India where people are strict vegetarian and I found hardly any people who stutter. However, in other states where people are non-vegeterians, based on information from my friends, they know many people who stutter.

Liem said...

I think that it would be easier to conceal one's stutter, ie. be a covert stutterer, in a language such as Chinese or Vietnamese, which are
1- Monosyllabic
2- Tonal

When speaking Vietnamese, I can stop after any word (syllable) without syntaxic disruption (unlike french or english). The tonality of the language gives a singing quality which helps too. This is perhaps why I have a much harder time with French than English, the latter being more rhythmical or emphatic.

I would appreciate your comments on this at gerald.trang@gmail.com
Cheers,
Deepest gratitude

Anna Deeter said...

Please, check out my last blog. I have found a very simple explanation of the well-known fact that people that speak languages that do not use letters for writing, hardly ever stutter! Chinese, Native American, and Australian Aboriginal language populations do not have this problem!

http://www.empowernetwork.com/adeeter/blog/new-answers-about-stuttering-statistics/?id=adeeter