A simple grammar formalism--dependency grammar--motivated by the observation that longer distance connections between words are harder to make. Syntax provides a cognitive basis for syntactic structures across languages. Edward Gibson observes that there is a cognitive cost associated with connecting words that increases with the dependency length, such that shorter connections are preferred. A transparent formalism to represent this observation is dependency grammar, in which a word is simply connected to another word via a dependency arc to form a larger compositional meaning. This formalism can explain numerous aspects of word order universals across languages.
This book contrasts dependency grammar with the industry standard going back to Chomsky's phrase structure grammar with transformations. Dependency grammar is a simpler formalism: it does not posit the existence of categories that combine words. Furthermore, there are no transformations. Gibson argues that a construction-based dependency grammar is not only simpler than a phrase structure with transformations approach, but it also accounts for language phenomena more effectively.
