Tag Archives: Dan Dediu

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The power of diversity: New Scientist recognises the growing work on social structure and linguistic structure

A feature article in last week’s New Scientist asks why there is so much linguistic diversity present in the world, and what are the forces that drive it.  The article reads like a who’s who of the growing field of language structure and social structure:  Mark Pagel, Gary Lupyan, Quentin Atkinson, Robert Munroe, Carol and Melvin Ember, Dan Dediu and Robert Ladd, Stephen Levinson (click on the names to see some Replicated Typo articles about their work).  This is practically as close as my subject will come to having a pull-out section in Vanity Fair.  Furthermore, it recognises the weakening grip of Chomskyan linguistics.

Commentators have already gotten hung-up on whether English became simplified before or after spreading, but this misses the impact of the article:  There is an alternative approach to linguistics which looks at the differences between languages and recognises social factors as the primary source of linguistic change.  Furthermore, these ideas are testable using statistics and genetic methods.  It’s a pity the article didn’t mention the possibility of experimental approaches, including Gareth Roberts’ work on emerging linguistic diversity and work on cultural transmission using the Pictionary paradigm (Simon Garrod, Nick Fay, Bruno Gallantucci, see here and here).

David Robson (2011). Power of Babel: Why one language isn’t enough New Scientist, 2842 Online

Genetic Anchoring, Tone and Stable Characteristics of Language

In 2007, Dan Dediu and Bob Ladd published a paper claiming there was a non-spurious link between the non-derived alleles of ASPM and Microcephalin and tonal languages. The key idea emerging from this research is one where certain alleles may bias language acquisition or processing, subsequently shaping the development of a language within a population of learners. Therefore, investigating potential correlations between genetic markers and typological features may open up new avenues of thinking in linguistics, particularly in our understanding of the complex levels at which genetic and cognitive biases operate. Specifically, Dediu & Ladd refer to three necessary components underlying the proposed genetic influence on linguistic tone:

[…] from interindividual genetic differences to differences in brain structure and function, from these differences in brain structure and function to interindividual differences in language-related capacities, and, finally, to typological differences between languages.”

That the genetic makeup of a population can indirectly influence the trajectory of language change differs from previous hypotheses into genetics and linguistics. First, it is distinct from attempts to correlate genetic features of populations with language families (e.g. Cavalli-Sforza et al., 1994). And second, it differs from Pinker and Bloom’s (1990) assertions of genetic underpinnings leading to a language-specific cognitive module. Furthermore, the authors do not argue that languages act as a selective pressure on ASPM and Microcephalin, rather this bias is a selectively neutral byproduct. Since then, there have been numerous studies covering these alleles, with the initial claims (Evans et al., 2004) for positive selection being under dispute (Fuli Yu et al., 2007), as well as any claims for a direct relationship between dyslexia, specific language impairment, working memory, IQ, and head-size (Bates et al., 2008).

A new paper by Dediu (2010) delves further into this potential relationship between ASPM/MCPH1 and linguistic tone, by suggesting this typological feature is genetically anchored to the aforementioned alleles. Generally speaking, cultural and linguistic processes will proceed on shorter timescales when compared to genetic change; however, in tandem with other recent studies (see my post on Greenhill et al., 2010), some typological features might be more consistently stable than others. Reasons for this stability are broad and varied. For instance, word-use within a population is a good indicator of predicting rates of lexical evolution (Pagel et al., 2007). Genetic aspects, then, may also be a stabilising factor, with Dediu claiming linguistic tone is one such instance:

From a purely linguistic point of view, tone is just another aspect of language, and there is no a priori linguistic reason to expect that it would be very stable. However, if linguistic tone is indeed under genetic biasing, then it is expected that its dynamics would tend to correlate with that of the biasing genes. This, in turn, would result in tone being more resistant to ‘regular’ language change and more stable than other linguistic features.

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ASPM, Microcephalin and Tone

ResearchBlogging.orgDisclaimer: I know this post is on a paper released over a year ago; however, I’m still going to write about it for three reasons: 1) I did a presentation about it earlier this week (20/01/08); 2) I think it relates to a recent buzz around gene-culture co-evolution; and, 3) It’s a bloody awesome paper.

So, what is the paper called? Okay, once you read this title, do not yawn, go to another website or… Linguistic tone is related to the population frequency of the adaptive haplogroups of the two brain size genes, ASPM and Mircocephalin. See, now we’ve got the hard part out of the way, I can begin to discuss exactly what the authors, Dan Dediu and Robert ‘Bob’ Ladd, found and why it’s important to our understanding of linguistics, genetics and evolution. It’s really interesting, honestly.
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