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.

翻译：尽管语言是一个复杂适应系统，但大多数关于句法变异的研究仅观察语法中孤立的若干特定结构。这意味着，作为连接不同抽象层级数千个结构的网络，语法被简化为若干互不关联的变量。本文通过系统建模16个国家49个英语方言人群的语域变异，量化了这种简化带来的影响。我们分别使用完整语法系统及其内部孤立节点进行方言分类，以刻画这些方言之间的句法差异。研究结果表明：首先，语法中的许多独立节点确实存在变异，但孤立节点的分类性能均低于完整语法系统，这表明句法变异的重要组成部分在于语法不同部分之间的相互作用。其次，结果显示方言间的相似度高度依赖于所观察的语法子集：例如，新西兰英语在短语动词层面与澳大利亚英语更相似，但同时在双宾语结构层面与英国英语更为接近。