Dependency grammar

These trees illustrate two possible ways to render the dependency and phrase structure relations (see below). This dependency tree is an "ordered" tree, i.e. it reflects actual word order. Many dependency trees abstract away from linear order and focus just on hierarchical order, which means they do not show actual word order. This constituency (= phrase structure) tree follows the conventions of bare phrase structure (BPS), whereby the words themselves are employed as the node labels.

There are major differences between the grammars just listed. In this regard, the dependency relation is compatible with other major tenets of theories of grammar. Thus like phrase structure grammars, dependency grammars can be mono- or multistratal, representational or derivational, construction- or rule-based.

There are various conventions that DGs employ to represent dependencies. The following schemata (in addition to the tree above and the trees further below) illustrate some of these conventions:

The point to these conventions is that they are just that, namely conventions. They do not influence the basic commitment to dependency as the relation that is grouping syntactic units.

The nature of the dependency relation does not, however, prevent one from focusing on linear order. Dependency structures are as capable of exploring word order phenomena as phrase structures. The following trees illustrate this point; they represent one way of exploring discontinuities using dependency structures. The trees suggest the manner in which common discontinuities can be addressed. An example from German is used to illustrate a scrambling discontinuity:

The syntactic functions in this tree are shown in green: ATTR (attribute), COMP-P (complement of preposition), COMP-TO (complement of to), DET (determiner), P-ATTR (prepositional attribute), PRED (predicative), SUBJ (subject), TO-COMP (to complement). The functions chosen and abbreviations used in the tree here are merely representative of the general stance of DGs toward the syntactic functions. The actual inventory of functions and designations employed vary from DG to DG.

As a primitive of the theory, the status of these functions is very different from that in some phrase structure grammars. Traditionally, phrase structure grammars derive the syntactic functions from the constellation. For instance, the object is identified as the NP appearing inside finite VP, and the subject as the NP appearing outside of finite VP. Since DGs reject the existence of a finite VP constituent, they were never presented with the option to view the syntactic functions in this manner. The issue is a question of what comes first: traditionally, DGs take the syntactic functions to be primitive and they then derive the constellation from these functions, whereas phrase structure grammars traditionally take the constellation to be primitive and they then derive the syntactic functions from the constellation.

This question about what comes first (the functions or the constellation) is not an inflexible matter. The stances of both grammar types (dependency and phrase structure) are not narrowly limited to the traditional views. Dependency and phrase structure are both fully compatible with both approaches to the syntactic functions. Indeed, monostratal systems, that are solely based on dependency or phrase structure, will likely reject the notion that the functions are derived from the constellation or that the constellation is derived from the functions. They will take both to be primitive, which means neither can be derived from the other.