Syntactic Variation Across the Grammar: Modelling a Complex Adaptive
  System
Jonathan Dunn
While language is a complex adaptive system, most work on syntactic variation
observes a few individual constructions in isolation from the rest of the
grammar. This means that the grammar, a network which connects thousands of
structures at different levels of abstraction, is reduced to a few disconnected
variables. This paper quantifies the impact of such reductions by
systematically modelling dialectal variation across 49 local populations of
English speakers in 16 countries. We perform dialect classification with both
an entire grammar as well as with isolated nodes within the grammar in order to
characterize the syntactic differences between these dialects. The results
show, first, that many individual nodes within the grammar are subject to
variation but, in isolation, none perform as well as the grammar as a whole.
This indicates that an important part of syntactic variation consists of
interactions between different parts of the grammar. Second, the results show
that the similarity between dialects depends heavily on the sub-set of the
grammar being observed: for example, New Zealand English could be more similar
to Australian English in phrasal verbs but at the same time more similar to UK
English in dative phrases.