# coordination

last changed in 2002

Notation: `{....}' round the words in the coordination.

`Coordination' is the name of a relationship which contrasts with `subordination'; `a coordination' is a word-string which is held together by this relationship. For example, green apples and red plums is a coordination, in which green apples is bound together with red plums by coordination. (In other words, they are coordinated.) This relationship is shown in WG notation by curly brackets round the coordinated words: {green apples and red plums}. The parts of the coordination are called its `conjuncts', and are shown by square brackets, so the full coordination analysis of this example is shown in (1).

(1) {[green apples] [and red plums]}

See conjunct for the reasons for including in each conjunct the whole word-string (e.g. green apples) rather than simply the root words (e.g. apples); and see coordinator for the (rather poor) reasons for including and in the second conjunct.

What is this relationship `coordination'? The basic idea is very simple: suppose two words A and B are related syntactically. There are only two logical possibilities: either A and B are equal in status, or they are unequal. If they are equal, they are coordinated, and if they are unequal, one is subordinate to the other - i.e. one depends on the other.

This distinction is a very traditional basis for grammatical theories; for instance, traditional grammar distinguishes `coordinating conjunctions' like AND from `subordinating conjunctions' such as BECAUSE. But what does it mean to say that two words are equal or unequal `in status'? What kind of status are we talking about? If the discussion is about how we want to define the terms the answer is just a matter of taste, but we can turn it into a question of fact by focussing on the differences between AND and BECAUSE.

We observe that AND is used differently from BECAUSE (e.g. Pat and/*because Jo), and we have decided to call the relationship marked by AND `coordination', so what are the rules for using AND? In what sense do the conjuncts linked by AND have to be `equal in status'?

One possibility that we can eliminate is that they (or their root-words) must belong to the same word-class; this is ruled out by examples such as (2) and (3).

(2) Pat is {[a good linguist] [and very clever]}.

(3) the {[national] [and London]} news

In (2) the conjuncts are a noun-phrase and an adjective-phrase, and in (3) they are an adjective and a noun, but the coordinations seem fine; such mixed-class coordinations are very common.

The WG view is that conjuncts must be `equal' in their external relations. This can be defined more precisely in terms of dependency - see Dependency-in-Coordination Principle. Roughly speaking, the roots of the conjuncts have to share the same external dependencies, so (2) is good because a (good linguist) and (very) clever both have the same dependency relation (sharer) to is, and (3) is good because national and London are both pre-adjuncts of news. Their structures are shown below.

The main point to remember about the WG analysis of coordination is that the coordination analysis, shown by the brackets, is quite separate from the dependency analysis. In fact, they are based on quite different principles.

• Whereas dependency analysis is based on the relations between pairs of individual words, coordination analysis is based on the relations between strings of words.
• Whereas the fundamental relationship in dependency analysis is (not surprisingly) dependency, the fundamental relationship in coordination is the part-whole relationship between the conjuncts and the whole coordination.

The two analyses apply to the same words (except that the coordinators are ignored by the dependency analysis), so they have to be compatible, but the only thing that counts towards compatibility is the Dependency-in-Coordination Principle.

A coordination has an internal structure which is defined by the grammar. Basically, it consists of at least two conjuncts, which between them account for all the words in the coordination:

{[...] [...]}

{[...] [...] [...]}

or any other combination of two or more conjuncts. (Sometimes it may not be clear where the coordination's first boundary is; see correlative conjunction for a simple test which often helps.)

This is all the grammar needs to say about the conjuncts as such, but there is more to say about the coordinators (e.g. AND). As explained in coordinator, we assume that each one is included in the conjunct that follows it, so a simple two-part coordination like Pat and Jo has the following structure (where C stands for the coordinator):

{[...] [C...]}

There are two complications.

• One is that the first conjunct may also be introduced by a special kind of coordinator, a `correlative conjunction'. Different main coordinators require different correlatives: BOTH with AND, EITHER with OR, and so on. This allows the following pattern:

{[C...] [C...]}

• The other complication is that if there are more than two conjuncts, coordinators may be added in either of two patterns:
• A. just a single coordinator in the last conjunct: Ann, Bill, Carol and Dennis.
• B. a separate coordinator in all but the first conjunct: Ann and Bill and Carol and Dennis.

Pattern A is an unambiguous sign of a single coordination, and only allows one analysis. For example, (4) must be analysed in such a way that the four people constitute a single group, which could play a quartet but could not play duets.

(4) {[Ann], [Bill], [Carol] [and Dennis]} played a quartet/!duet.

In contrast, pattern B could be interpreted in this way, but could also be bracketed into two pairs (or indeed into a trio and a singleton), giving two analyses of (5):

(5) {[Ann] [and Bill] [and Carol] [and Dennis]} played a quartet/!duet.

(5') {[{[Ann] [and Bill]}] [and {[Carol] [and Dennis]} played a duet/!quartet.

(See nested coordination for this last pattern.) In pattern B the coordinators must all be the same, so if they vary there must be further coordinations inside the largest one; for example in Ann and Bill or Carol and Dennis there must be three coordinations, one for each coordinator, though they may be grouped in three different ways:

{[Ann] [and {[Bill] [or {[Carol] [and Dennis]} ]} ]}

{[ {[ {[Ann] [and Bill]} ] [or Carol]} ] [and Dennis]}

{[ {[Ann] [and Bill]} ] [or {[Carol] [and Dennis]} ]}

This is an article from the Encyclopedia of Word Grammar and English grammar. If you refer to it, please give the url as "http://tinyurl.com/wg-encyc".