New Languages Rapidly Spring From Old Ones
Scientists for decades have clashed over whether evolution takes place gradually or is driven by short spurts of intense change.
In the latest chapter in this debate, researchers report in Science this week that it appears that when new languages spin-off from older ones, there is an initial introductory burst of alterations to vocabulary. Then, the language tends to settle and accumulate gradual changes over a long period of time. The team believes this discrete evolutionary pattern occurs when a social group tries to forge a separate identity.
Study co-author Mark Pagel, an evolutionary biologist at the University of Reading in England, says that the latest study grew out of an earlier finding in which he and colleagues determined that about 20 percent of genetic changes among species occur when they first split off, whereas the rest happen gradually.
"It was very natural for us to wonder if a similar process [of evolution] happens in cultural groups," Pagel says. "We treat the words that different languages use almost identically to the way we use genes: … The more divergent two species are, the less their genes have in common, just as the more divergent two languages are, the less their words have in common."
The team focused on three of the world's major language families in its study: Bantu (Swahili, Zulu, Ngumba, for example), Indo-European (English, Latin, Greek, Sanskrit) and Austronesian (South Pacific and Indian Ocean languages such as Taglaog or Seediq). They constructed genealogical trees—similar to those they had created previously in their 2006 species-related study—albeit this time the trees traced existing languages back to their common roots; the length of a "branch" indicated the extent of word replacement that took place as each old language morphed (possibly with new languages splitting off) into its current form.
Saturday, February 2, 2008
Scientific American examines language evolution.