In the United States there are currently two major varieties of diagrams in use to represent sentence structure: traditional diagrams, used more or less exclusively in junior high school and high school classrooms, and tree diagrams, the most common method used by professional linguists.

The traditional system has lost much of its former popularity but is still to be found in the back of many schoolbooks. Such diagrams, with words tilted at odd angles, with lines forming inscrutable patterns and extending quaquaversally to the edges of the page, remain the image most readily evoked for non-linguists, even if fewer and fewer people are forced to draw them by their ninth-grade English teachers.

These illustrations are known as Reed-Kellogg diagrams, named after Alonzo Reed and Brainerd Kellogg, who described their method in two books first published in the 1870s: Graded Lessons in English (1875) and Higher Lessons in English (1877). A simple example is shown to the right.

The Reed-Kellogg diagram is a tool of the classroom and of the textbooks that codify the rules for its production. But grammar textbooks share a problem similar to the one Thomas Kuhn noted for science textbooks: they tend to efface the history of their subject. Indeed, grammar textbooks are far more ahistorical that science textbooks. The average science textbook will contain some history, however Whiggish. There will be at least a cursory mention of the scientists who formulated the theories under discussion, some suggestion that scientific knowledge is subject to change and accretion. Grammar, however, comes to students as an abstract whole. The sources from which the textbook authors derived their accounts normally go unacknowledged. There is no sense of grammar as a theory—or, more precisely, a constellation of competing theories—with its own intellectual history.

Reed and Kellogg were not the first to represent sentence structure visually. Their diagrams encode one late-nineteenth-century view of English grammar and their attempt to find a more effective way to teach it. Moreover, the assumptions behind the diagrams were vigorously debated throughout the nineteenth century. What, then, led Reed-Kellogg diagrams to displace earlier schemes? When we turn to look at Reed and Kellogg's predecessors, another surprising fact emerges: sentence diagrams themselves appeared only in the middle of the nineteenth century, about thirty years before Reed and Kellogg introduced their system. But writers had been publishing studies of English grammar for centuries by that point. Why did it take so long for diagrams to develop?

Although the overall evolution of grammatical pedagogy has been studied by a number of writers, diagrams themselves have
not attracted much attention. Kitty Burns Florey has published a popular account of sentence diagrams, Sister Bernadette's Barking Dog (Florey, 2006), which contains modest historical detail and a large amount of impressionistic reaction to diagrams as she encountered them in her own schooling. In a more scholarly vein, Richard Brittain's PhD dissertation (Brittain, 1973) serves as a useful catalog of those grammarians who employed diagrams in their work. Brittain, however, is mostly concerned with judging how adequate the systems were with respect to transformational-generative syntax as it was understood in the early 1970s. His account provides minimal historical context and does not try to explain the reasons for the sudden appearance of diagrams in the middle of the nineteenth century.[1]

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(This page last updated Oct. 17, 2015)

Notes

1. I would like to thank Frank Schumacher for making a copy of Brittain's dissertation available to me.