Constituency and Dependency
The connections to modern principles for constructing parse trees are present in the Reed-Kellogg diagrams, although Reed and Kellogg were certainly unknowingly employing these principles. The principles are now understood as the constituency relation of phrase structure grammars and the dependency relation of dependency grammars. These two relations are illustrated here adjacent to each other for comparison:
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- (D = Determiner, N = Noun, NP = Noun Phrase, S = Sentence, V = Verb, VP = Verb Phrase)
Constituency is a one-to-one-or-more relation; every word in the sentence corresponds to one or more nodes in the tree diagram. Dependency, in contrast, is a one-to-one relation; every word in the sentence corresponds to exactly one node in the tree diagram. Both parse trees employ the convention where the category acronyms (e.g. N, NP, V, VP) are used as the labels on the nodes in the tree. The one-to-one-or-more constituency relation is capable of increasing the amount of sentence structure to the upper limits of what is possible. The result can be very "tall" trees, such as those associated with X-bar theory. Both constituency-based and dependency-based theories of grammar have established traditions.
Reed-Kellogg diagrams employ both of these modern tree generating relations. The constituency relation is present in the Reed-Kellogg diagrams insofar as subject, verb, object, and/or predicate are placed equi-level on the horizontal base line of the sentence and divided by a vertical or slanted line. In a Reed-Kellogg diagram, the vertical dividing line that crosses the base line corresponds to the binary division in the constituency-based tree (S → NP + VP), and the second vertical dividing line that does not cross the baseline (between verb and object) corresponds to the binary division of VP into verb and direct object (VP → V + NP). Thus the vertical and slanting lines that cross or rest on the baseline correspond to the constituency relation. The dependency relation, in contrast, is present insofar as modifiers dangle off of or appear below the words that they modify.
Read more about this topic: Sentence Diagram
Famous quotes containing the words constituency and/or dependency:
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