Reed-Kellogg diagram

In pedagogy and theoretical syntax, a sentence diagram or parse tree is a pictorial representation of the grammatical structure of a sentence. The term "sentence diagram" is used more in pedagogy, where sentences are diagrammed. The term "parse tree" is used in linguistics (especially computational linguistics), where sentences are parsed. The purpose of sentence diagrams and parse trees is to have a model of the structure of sentences. The model is informative about the relations between words and the nature of syntactic structure and is thus used as a tool to help predict which sentences are and are not possible.

Most methods of diagramming in pedagogy are based on the work of Alonzo Reed and Brainerd Kellogg in their book Higher Lessons in English, first published in 1877, though the method has been updated with recent understanding of grammar. Reed and Kellogg were preceded, and their work probably informed, by W. S. Clark, who published his "balloon" method of depicting grammar in his 1847 book A Practical Grammar: In Which Words, Phrases & Sentences are Classified According to Their Offices and Their Various Relationships to Each Another.

Some schoolteachers continue to use the Reed–Kellogg system in teaching grammar, but others have discouraged it in favor of more modern tree diagrams. However, these modern tree structures draw on techniques that were already present in Reed–Kellogg diagrams. Reed and Kellogg defend their system in the preface to their grammar:

The Objections to the Diagram.--The fact that the pictorial diagram groups the parts of a sentence according to their offices and relations, and not in the order of speech, has been spoken of as a fault. It is, on the contrary, a merit, for it teaches the pupil to look through the literary order and discover the logical order. He thus learns what the literary order really is, and sees that this may be varied indefinitely, so long as the logical relations are kept clear.

The assertion that correct diagrams can be made mechanically is not borne out by the facts. It is easier to avoid precision in oral analysis than in written. The diagram drives the pupil to a most searching examination of the sentence, brings him face to face with every difficulty, and compels a decision on every point.

These statements bear witness to the fact that Reed–Kellogg diagrams abstract away from actual word order in order to focus more intently on how words in sentences function and relate to each other.

...
Wikipedia