Phonetic Clues Hint Language Is Africa-Born
By NICHOLAS WADE
Published: April 14, 2011
A researcher analyzing the sounds in languages spoken around the world
has detected an ancient signal that points to southern Africa as the
place where modern human language originated.
The finding fits well with the evidence from fossil skulls and DNA
that modern humans originated in Africa. It also implies, though does
not prove, that modern language originated only once, an issue of
considerable controversy among linguists.
The detection of such an ancient signal in language is surprising.
Because words change so rapidly, many linguists think that languages
cannot be traced very far back in time. The oldest language tree so
far reconstructed, that of the Indo-European family, which includes
English, goes back 9,000 years at most.
Quentin D. Atkinson, a biologist at the University of Auckland in New
Zealand, has shattered this time barrier, if his claim is correct, by
looking not at words but at phonemes — the consonants, vowels and
tones that are the simplest elements of language. Dr. Atkinson, an
expert at applying mathematical methods to linguistics, has found a
simple but striking pattern in some 500 languages spoken throughout
the world: A language area uses fewer phonemes the farther that early
humans had to travel from Africa to reach it.
Some of the click-using languages of Africa have more than 100
phonemes, whereas Hawaiian, toward the far end of the human migration
route out of Africa, has only 13. English has about 45 phonemes.
This pattern of decreasing diversity with distance, similar to the
well-established decrease in genetic diversity with distance from
Africa, implies that the origin of modern human language is in the
region of southwestern Africa, Dr. Atkinson says in an article
published on Thursday in the journal Science.
Language is at least 50,000 years old, the date that modern humans
dispersed from Africa, and some experts say it is at least 100,000
years old. Dr. Atkinson, if his work is correct, is picking up a
distant echo from this far back in time.
Linguists tend to dismiss any claims to have found traces of language
older than 10,000 years, "but this paper comes closest to convincing
me that this type of research is possible," said Martin Haspelmath, a
linguist at the Max Planck Institute for Evolutionary Anthropology in
Leipzig, Germany.
Dr. Atkinson is one of several biologists who have started applying to
historical linguistics the sophisticated statistical methods developed
for constructing genetic trees based on DNA sequences. These efforts
have been regarded with suspicion by some linguists.
In 2003 Dr. Atkinson and Russell Gray, another biologist at the
University of Auckland, reconstructed the tree of Indo-European
languages with a DNA tree-drawing method called Bayesian phylogeny.
The tree indicated that Indo-European was much older than historical
linguists had estimated and hence favored the theory that the language
family had diversified with the spread of agriculture some 10,000
years ago, not with a military invasion by steppe people some 6,000
years ago, the idea favored by most historical linguists.
"We're uneasy about mathematical modeling that we don't understand
juxtaposed to philological modeling that we do understand," Brian D.
Joseph, a linguist at Ohio State University, said about the Indo-
European tree. But he thinks that linguists may be more willing to
accept Dr. Atkinson's new article because it does not conflict with
any established area of linguistic scholarship.
"I think we ought to take this seriously, although there are some who
will dismiss it out of hand," Dr. Joseph said.
Another linguist, Donald A. Ringe of the University of Pennsylvania,
said, "It's too early to tell if Atkinson's idea is correct, but if
so, it's one of the most interesting articles in historical
linguistics that I've seen in a decade."
Dr. Atkinson's finding fits with other evidence about the origins of
language. The Bushmen of the Kalahari Desert belong to one of the
earliest branches of the genetic tree based on human mitochondrial
DNA. Their languages belong to a family known as Khoisan and include
many click sounds, which seem to be a very ancient feature of
language. And they live in southern Africa, which Dr. Atkinson's
calculations point to as the origin of language. But whether Khoisan
is closest to some ancestral form of language "is not something my
method can speak to," Dr. Atkinson said.
His study was prompted by a recent finding that the number of phonemes
in a language increases with the number of people who speak it. This
gave him the idea that phoneme diversity would increase as a
population grew, but would fall again when a small group split off and
migrated away from the parent group.
Such a continual budding process, which is the way the first modern
humans expanded around the world, is known to produce what biologists
call a serial founder effect. Each time a smaller group moves away,
there is a reduction in its genetic diversity. The reduction in
phonemic diversity over increasing distances from Africa, as seen by
Dr. Atkinson, parallels the reduction in genetic diversity already
recorded by biologists.
For either kind of reduction in diversity to occur, the population
budding process must be rapid, or diversity will build up again. This
implies that the human expansion out of Africa was very rapid at each
stage. The acquisition of modern language, or the technology it made
possible, may have prompted the expansion, Dr. Atkinson said.
"What's so remarkable about this work is that it shows language
doesn't change all that fast — it retains a signal of its ancestry
over tens of thousands of years," said Mark Pagel, a biologist at the
University of Reading in England who advised Dr. Atkinson.
Dr. Pagel sees language as central to human expansion across the
globe.
"Language was our secret weapon, and as soon we got language we became
a really dangerous species," he said.
In the wake of modern human expansion, archaic human species like the
Neanderthals were wiped out and large species of game, fossil evidence
shows, fell into extinction on every continent shortly after the
arrival of modern humans.
A version of this article appeared in print on April 15, 2011, on page
A1 of the New York edition
--
You received this message because you are subscribed to the "USA-Africa Dialogue Series" moderated by Toyin Falola, University of Texas at Austin.
For current archives, visit http://groups.google.com/group/USAAfricaDialogue
For previous archives, visit http://www.utexas.edu/conferences/africa/ads/index.html
To post to this group, send an email to USAAfricaDialogue@googlegroups.com
To unsubscribe from this group, send an email to USAAfricaDialogue-
unsubscribe@googlegroups.com
No comments:
Post a Comment