Literature

We all know that language changes with time: new words, obsolete words, changed meanings, making verbs from nouns, etc. Many are familiar with the old English words "thou" and "thee" and their associated verb endings. Even earlier, English had no standard spellings and many words were used that are strange to our modern ears. Last year, two papers were highlighted here that documented patterns of change that have affected contemporary languages.

The invention of words requires intelligent agency

Those papers were loking at incremental changes with time within languages, and a crude analogy could be drawn with microevolution and Darwinian gradualism. Now, some of these authors have published on the origin of languages. Their study of Bantu, Indo-European, Austronesian, and Polynesian languages shows that "up to one-third of their words arose in rapid evolutionary bursts from the predecessor tongue". Again, the focus has been on vocabulary (there's more to say on this, but it is outside the scope of this blog). The authors write:

"We studied punctuational evolution in phylogenetic trees of language families inferred from vocabulary data. These trees describe the separate paths of evolution leading from a common ancestral language to the set of observed extant languages at the tips of the tree. The lengths of the individual branches of the trees record the amount of lexical divergence (replacement of words) between an ancestral and a descendant language. If lexical divergence is a gradual process that is not affected by the emergence of a new language, then the path length or total distance from the root of the tree to the languages at the tips should be independent of the number of language-splitting events or nodes found along that path. If language-splitting events produce punctuational bursts of evolution, however, we expect to find more total lexical divergence (longer path lengths) along paths through the tree that record more language-splitting events."

They demonstrate that their analysis leads to the conclusion that languages emerged abruptly, in a way that is distinct from the gradualism of subsequent changes.
The New Scientist report quotes one skeptical scholar:

Salikoko Mufwene a linguist at the University of Chicago, however, says it may be misleading to characterise language evolution as "abrupt". "You don't go to bed speaking one way and wake up speaking another way," he says. "Languages may change over centuries, but that is not abrupt, that is gradual."

This looks a bit like the reaction of Darwinists to the theory of Punctuated Equilibria: they just cannot escape from a gradualist mindset. It is significant, of course, that languages are spoken by intelligent agents. Consequently, the theoretical framework for understanding these changes should necessarily include inputs by intelligent agents. This emerges from a comment received last year by a linguist friend:

"One interesting development in the last century was the emergence of Nicaraguan Sign language, an entirely new language developed by deaf children under the age of 11 who were all sent to a new boarding school for deaf children. Older children developed a pigeon form with little grammar but a comprehensive vocabulary. The younger children had a fully formed grammar. It was certainly deemed as complex as American Sign Language. These children had had no contact with any other signing children, so developed the language de novo from their innate abilities."

The root problem appears to be that gradualism is a prevailing philosophy in the historical sciences. It is Lyellian: if it is not something we can study today, it does not count as science. But the data are telling us that things have happened in the past that go beyond our present experience. Perhaps we ought to be listening.

Languages Evolve in Punctuational Bursts
Quentin D. Atkinson, Andrew Meade, Chris Venditti, Simon J. Greenhill, and Mark Pagel.
Science, 319, 1 February 2008: 588.

Abstract: Linguists speculate that human languages often evolve in rapid or punctuational bursts, sometimes associated with their emergence from other languages, but this phenomenon has never been demonstrated. We used vocabulary data from three of the world's major language groups - Bantu, Indo-European, and Austronesian - to show that 10 to 33% of the overall vocabulary differences among these languages arose from rapid bursts of change associated with language-splitting events. Our findings identify a general tendency for increased rates of linguistic evolution in fledgling languages, perhaps arising from a linguistic founder effect or a desire to establish a distinct social identity.

See also:

Holden, C. Punctuation Marks in Language Evolution? ScienceNOW Daily News, 31 January 2008

McKenna, P. Languages evolve in sudden leaps, not creeps, NewScientist.com, 01 February 2008