The speakers of tonal and non-tonal languages have genetic differences

[david1978]

Hey, guys: I pulled this article from the economist. I'd love to hear your thoughts (if you have any). Cheers.

Linguistics

Words in code

May 31st 2007

From The Economist print edition

The speakers of tonal and non-tonal languages have genetic differences

FIVE years ago three well-known academics, including Noam Chomsky, wrote that the half-century old “interdisciplinary marriage” between biology and linguistics “has not yet been fully consummated.” That same year other scientists described the molecular evolution of a gene called FOXP2 which, when mutated, seems to cause people severe difficulty with grammar and articulation.

Another genetic condition that could shed light on the biology of linguistics is microcephaly (sometimes rudely called “pin-headedness”). It is linked to six genes, a spanner in the works of any of which leads the human brain to grow to only two-thirds of a pint in adults. That is less than a third of its normal volume. Those genes are alluring objects for studying the evolution of language because brain size has ballooned in people since their line split with that of their closest relatives. Even though birds sing and bees dance, nothing in nature matches a human's richly complicated system of vocal communication. In short, language makes humans unique and genes active in the developing brain make language possible.

Dan Dediu and Robert Ladd, of the University of Edinburgh, are helping biology and linguistics become intimate at the genetic level. In the current issue of the Proceedings of the National Academy of Sciences they describe a statistical analysis of two of the genes that cause microcephaly when they go wrong. Like many genes, both exist in different functional versions, called alleles, which are spread unevenly among human populations.

First, Dr Dediu and Dr Ladd checked that their two genes of interest really are unusual. They combined a database of 983 alleles that are known to vary across human groups with another enumerating how 26 discrete linguistic features (such as whether consonants aggregate at the beginnings and ends of words) are either used or not used in conversation by 49 populations. Picking apart a thicket of possible correlations, Dr Dediu and Dr Ladd found no general links between human genetic and linguistic characters.

But one feature—whether a language uses pitch as well as vowels and consonants to convey word meanings—stood apart. Those, such as Chinese, that encipher meaning in pitch are called “tonal languages”. Those that do not, like English, are “non-tonal”. And it was versions of Dr Dediu's and Dr Ladd's two microcephaly-related genes that matched the 49 populations along tonal and non-tonal lines.

Dr Dediu and Dr Ladd believe the evolution of tonal and non-tonal languages interacted with the evolution of these genes. Certain alleles could have predisposed people to a tonal-language structure. That tonal language, if used by individuals with whom communicating well is particularly helpful, could then reinforce selection for those alleles. Probably not coincidentally, the two alleles that are associated with non-tonal languages evolved recently in human history (some 5,800 and 37,000 years ago) and show signs of being strongly beneficial to their carriers.

Correlations such as these can shift the balance of evidence, but it is demonstrating causation in addition to correlation that forms the glue of the scientific method. Here the marriage between language and genetics hits a problem. No suspicious-looking gene can be added or eliminated in an experimental mouse in order to discover its effects on language, since mice cannot speak. At best, researchers can try to fill in gaps between molecular biology and behaviour.

In March, Narly Golestani and her colleagues at University College, London, showed that people who are fast at learning the sounds of foreign speech have more densely packed white matter in a part of the brain called the left Heschl gyrus. Patrick Wong and his colleagues at the University of Texas, Austin, recently found that adult English speakers fall into two groups, according to their ability to learn tonal distinctions. The more successful also had bigger left Heschl gyruses. The next task is to see if genetic differences can be pinned on the two groups—and, if so, exactly which genes are involved.

[wrbt]

A person of Chinese descent who grew up in the United States sounds just like everyone else in their area.

I would assume a Westerner who was born and raised in China by Chinese parents would sound exactly the same as other Chinese... has anyone encountered someone like that?

Taking it further can we assume a Westerner or Asian who was raised in a part of Africa that uses those clicking noises in verbal communication would click like a native?

[Luobot]

has anyone encountered someone like that?

Yes.

I don’t disagree that there is some validity to their hypothesis. But they haven’t proven that they’ve found the only genes involved in tonal language production. Born with them and you’re good to go; otherwise, you’re a fish trying to stand up and walk on two legs. Like the whole “nature vs. nurture” debate, our environment causes our genes, which we all for the most part share, to express themselves to a greater or lesser extent. I may have been born with less tonal aptitude than a full blooded Chinese person (and less than many westerners, for that matter), but I can still develop my potential for tonal languages through practice. I’ll just have to make a greater effort … and remember to stop blaming my mother.

[muyongshi]

So what happens if we throw a variable into the mix? Specifically being tone deaf.

I'm not kidding hear...tone deafness as far as I understand is not a "gene related" condition.

I have a friend who is tone deaf and on individual words, some how she can get the rising and falling but can never get tones when listening to someone or trying to speak in sentences (this is a foreigner) and my guess is that out of 1.3 billion people there are a few who are tone deaf. Does that affect their ability to speak a tonal language.

And just so no one butchers me about definition I am not saying that their is a connection (directly) between "tone deaf" and "tonal language". I do know that they are different things and just happen to contain the word "tone".

Anyway just a thought. I don't know, it's interesting to consider. Any thoughts?

[simonlaing]

Hey WRBT,

As someone who lived in country with a Clicking language,(Zimbabwe, southern tribal language Ndebele) I can tell you westerners can learn this language. It is not as complicated as a tonal (i.e. Chiense ) language either. The sound comes from the tongue placement in the mouth when you start the click and the shape of the mouth and lips.

Also in China I have met a couple western people who lived most of their lives here or in Hong Kong from childhood and seem to have excelllant tones.

As you say it may not be one or the other .

I heard other psychology opinions that the child's brain grows and develops very fast at a younger age and thus it is easier to learn languages then as it is easier to make new memories and skill learning. Many child experts use this rationale to argue children should learn several languages when they are young.

Have fun,

SimoN:)

[muyongshi]

Yeah there is something hypothesized by linguistics and psychologist called the "LAD" or Language Acquisition Device. Google it if you want the full definition but it has to do with the way we acquire or first or mother language and would apply hear to children being raise in a bilingual environment.

Basically I don't think any language is impossible. Some are harder and require harder work. But whether or not genes effect our ability to learn certain ones...the jury is still out.

[zhwj]

This analysis (and the subsequent response linked at the end) may be enlightening. There's something going on, but it's certainly not the "genes help you learn Chinese" that is bandied about in headlines.

[imron]

I have a friend who is tone deaf and on individual words, some how she can get the rising and falling but can never get tones when listening to someone or trying to speak in sentences (this is a foreigner) and my guess is that out of 1.3 billion people there are a few who are tone deaf. Does that affect their ability to speak a tonal language.

Just out of curiousity, how does your friend deal with changes of tone in the English language? Can she distinguish between a question and a statement when the only difference is the change of intonation at the end?

This thread discusses some of these things in more detail.

[gougou]

I believe that genetics can play a role in predisposing a nation to a tonal language, but I think what's more important to us learners is the upbringing. If I hadn't been drilled to raise my pitch at the end of a question for twenty-some years, I'm sure I'd have much less trouble with Chinese tones now.

[imron]

Moved the discussion on language fluency to this thread.

[david1978]

Thanks, Imron.

[muyongshi]

Hey imron about my friend as far as I understand it is difficult without a third factor (ie facial expressions). That's all i know

[wrbt]

So who has a harder time trying to speak like a native... a tone deaf Chinese person or an Italian born without hands?

[kudra]

as they said in the article, there is no evidence of a causal link between the gene and tonality of language.

I looked at their web site a few weeks ago when the Economist article came out. If I read their summary right, one thing they did not do is consider the prior existing evolutionary relationship among the tonal language speakers in their sample.

Suppose the speakers of tonal languages, and only the tonal speakers, belong to one sub-tree of the human family tree of the people in the sample. Then the existence of the gene in that sub-tree is less significant. If on the other hand, the placement of the tonal language speakers is "sprinkled" around in separate subtrees of exclusively tonal speakers, and the gene is also specific to those subtrees, then it is more likely that the gene might have something to do with a predisposition to develop tonal language. This is called a phylogenetic analysis. The authors of this study did not do such an analysis. However, since the tonal languages appear in both Africa and China (they have some cool geographic plots of the gene frequency and language tonality), they might have this covered. If I remember I’ll ask an expert that I know.

quoting from their summary:

This means that our approach is different from the well-known work of Cavalli-Sforza and his colleagues, which aims to correlate genetic and linguistic classifications of populations, using known or hypothesised historical relations between languages and language families (do populations genetically similar tend to be also linguistically similar? - where genetic similarity involves many independent loci and linguistic similarity involves historical, ancestor-descendant relationships). Our work investigates correlations between genetic markers and typological features of languages (do populations having certain alleles tend to speak languages using the same feature? - without reference to overall genetic similarity or linguistic historical classifications).

Here is a link to their summary.

The other thing they stress is that these results have no significance for individual learners.

We believe that this correlation may reflect some sort of predisposition or cognitive bias induced by the two genes in question. We don’t have any detailed idea of what this bias might consist of, but we assume it is very small and would only manifest itself in language change over many generations. We know, of course, that any normal human infant can learn the language of any human community that it’s brought up in – genes don’t play any role at the individual level. But subtle differences in the way children acquire language might lead to changes in the long run. All languages change over time (as anyone who has struggled with Shakespeare knows), and computer simulations and mathematical models have suggested that small differences in the way children acquire language could, over enough generations, give rise to big differences in the way a language is structured. And if those subtle differences are influenced by a child’s genetic make-up, that could explain the kind of correlation we’ve found.

The bold face bit, pretty much puts the lie to all the headlines that pop up when you google for the authors, Dan Dediu and Robert Ladd.

[muyongshi]

We know, of course, that any normal human infant can learn the language of any human community that it’s brought up in – genes don’t play any role at the individual level.

Ｉ think this point is proven numerous times and while genes may play a role in our language （notice Ｉ didn't say language acquisition） they do not determine the ability to speak a language or not.

Ａ big part of the pronunciation is about the form of the mouth. Ａnd Ｉ don't mean whether or not u do a kissy face when saying 鱼. Ｉ mean that our mouths and palletes are formed as we grow to suit the pronunciation that we learn as a kid. Ｔhis is proven. Ｉn the Ｃhinese language the tongue hits at different points than an Ｅnglish speaker's. Ｓo the child's mouth forms to those points until they are about 14 and then the mouth begins to really harden to his adult form.