Imagine that you are sitting at a small table covered with Lego pieces of every kind: square ones, rounded sections, long bricks, and those flat rectangles that are so annoying to take apart. By themselves, these plastic blocks are not very useful. You could look at each one individually and identify its shape and color, but until you pick the pieces up and start connecting them, all you will have is a pile of bricks.
When students learn the parts of a sentence, they are collecting their own grammar pieces. They memorize, for example, that a direct object answers the question “who” or “what” and receives the action of a verb. They learn that a predicate nominative follows a linking verb and renames a subject. But they don’t always learn how those parts work together, and diagramming sentences is one of the best tools we have to show students how to connect these pieces and construct a good sentence.
Let’s say that a student adds a prepositional phrase to a sentence, in order to give some nice detail and add description. If a student has practiced diagramming, she will know, from seeing how the lines of the diagram connect, what word this prepositional phrase is modifying. If that
phrase is acting as an adjective, the placement in the sentence becomes even more important. Here’s an example fromGrammar for the Well-Trained Mind:
Inside the clock, Daniel watched the huge, swinging pendulum.
In this sentence, the prepositional phrase “Inside the clock” is in the wrong spot. Diagramming this phrase forces a student to make a decision: Is this phrase acting as an adjective or adverb? Does it belong under (modify) the word “watched” or something else? Is the pendulum inside the clock or is Daniel? Once a student recognizes this phrase as adjectival, she would then realize that the phrase is a misplaced modifier, and that it needs to be put directly after the noun “pendulum.”
Diagramming sentences creates a visual representation for the student of how the sentence parts she has studied all click together. It gives younger students a chance to try out some critical thinking skills and learn a bit of analysis, and it allows more experienced students to see how various types of clauses and structures all work together to create a lovely-sounding group of words, much like how that jumbled pile of Lego bricks can, once connected, become something to enjoy.
It is our hope that, if you have never diagrammed before, our grammar classes will introduce you to a new, useful tool for you and your students as you craft your phrases and clauses and paragraphs. Happy diagramming!