Consequences of the Exaptation of Dialect Diversity for Social Marking

Daniel Livingstone
School of Information and Communication Technology, University of Paisley
daniel.livingstone@paisley.ac.uk

The application of dialect variation to social marking - allowing
members of groups to easily identify outsiders - has been noted in many
studies, although there has been some debate over the extent to which it
has driven language change and variation.  Dunbar (1996) and Nettle
(1999) argue that the adaptive benefits of social marking promote the
evolution of dialect diversity, while Milroy (1993, p.215) argues a
complementary point that a social benefit arising from dialect
differences must exist for significant language changes to occur as
readily as they do. 

We have previously presented counter arguments that it is more likely
that social marking is, in effect, an exaptation, a novel use of a
spandrel formed by the natural emergence of dialect diversity, such
diversity being a consequence of the acquisition of language in
spatially distributed populations (Livingstone, 2000). 

Assuming that diversity will emerge regardless of adaptive benefits, it
remains to be answered how the adoption of dialect differences to act as
social markers might influence the continued evolution of dialects and
linguistic diversity. 

Here we present the preliminary findings of the effect of social
influence and marking on computer simulations of the evolution of vowel
systems in spatially distributed populations.  We use de Boer's (2000)
phonological model for the individual agents, within a population whose
arrangement, replacement and migration patterns are based on Nettle's
(1999) model.  This allows for ready comparison against Nettle's
findings, as well as matching closely to a much earlier model - one used
over a century ago in a thought experiment which supposes, "a large
plain covered with villages of equal size and independence at equal
distances" (Sweet, 1888, p.52).  We find that with no social influence
in the model a dialect continuum is formed - just as Sweet anticipated. 
We then add social influence as a factor in the acquisition of vowel
systems and compare the dialect diversity found against that found when
social influence has no part to play. 


de Boer, B.  (2000).  Emergence of Sound Systems through
Self-Organisation.  In The Evolutionary Emergence of Language: Social
Function and the Origins of Linguistic Form.  C.  Knight, M. 
Studdert-Kennedy and J.  R.  Hurford (Eds.), Cambridge University Press:
177-198. 

Dunbar, R.  (1996).  Grooming, Gossip and the Evolution of Language,
Faber & Faber. 

Livingstone, D.  (2000).  A Modified-Neutral Theory for the Evolution of
Linguistic Diversity.  In The 3rd International Conference on the
Evolution of Language, Paris. 

Milroy, J.  (1993).  On the Social Origins of Language Change.  In
Historical Linguistics: Problems and Perspectives.  C.  Jones (Ed.). 
London, New York, Longman. 

Nettle, D.  (1999).  Linguistic Diversity, Oxford University Press. 

Sweet, H.  (1888).  The History of English Sounds.  Oxford, Clarendon
Press.