The Architecture of a Sentence

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When I was in grade school during the early 1960’s, we learned a skill that is not used very often today. We learned how to “diagram a sentence.” If you’ve never heard that phrase before, diagramming basically allows you to see how the words of a sentence work together to express an idea. I call it the architecture of a sentence. And just as a blueprint can help an architect or an engineer construct a beautiful building, knowing how to a diagram a sentence can help you craft your ideas into essays that are clear and precise.

The basic structure of a sentence diagram is a horizontal line bisected by a vertical line, and you place the verb (the action word) to the right of the vertical line and the noun (the person, place, thing, or idea) to the left. The noun is called the Subject of the sentence, and the verb is called the Predicate. Thus, the simple sentence “Maggie dances” would look like this.

Since we typically use more than two words in our sentences, we also need to include adjectives and adverbs, the words that describe nouns and verbs. However, since the adjectives and adverbs are secondary to the main idea of the sentence, they are placed on slanted lines below the corresponding nouns and verbs. So, if we want to diagram the sentence “Beautiful Maggie dances gracefully,” the picture would look like this.

Two other parts of speech that may be present in a sentence are prepositions and conjunctions. Prepositions — words such as “to, from, over, and under” — often show where the action of a sentence takes place, and they connect these locations (nouns) to the rest of the sentence but on a level below the main horizontal line. The preposition and the noun that follows are called a prepositional phrase. Conjunctions, meanwhile, are joining words, and they are usually placed on a dotted line between the connected words. Three of the most common conjunctions are “and, but, and or.” So, if we extend our sentence, we see that “Beautiful Maggie dances gracefully at home and at work.”

Finally, the last two parts of speech are pronouns and interjections. Pronouns are words like “I, you, he, she, it, we, and they,” and these words take the place of nouns. As a result, pronouns usually show up on the horizontal lines that usually contain nouns. Similarly, interjections are also placed on horizontal lines, but these words — words that typically express strong emotion — are placed on a separate line above the sentence. Thus, the sentence “Wow! She dances gracefully” would be diagrammed in this way.

In addition to the previously mentioned Subject and Predicate, some sentences also have a Direct Object which receives the action of the verb. If we wrote “Maggie bought the gift,” the Direct Object would be the word “gift” because it answers the question “What did Maggie buy?” On the diagram, the Direct Object is added on the main horizontal line to the right of the verb, and a short vertical line separates the verb from the Direct Object. We could also add an Indirect Object which receives the noun of the Direct Object. In other words, it lets the reader know that Jim is the recipient of the gift, and the Indirect Object is placed on a horizontal line below the verb: “Maggie bought Jim the gift.” (If that same sentence also included the preposition “for,” then what was considered an Indirect Object would be converted to a prepositional phrase.)

Finally, some sentences also have a Subject Complement. The Subject Complement is an adjective that describes the subject, and this adjective is placed to the right of the verb on the main horizontal line. This is a rare case where an adjective is placed on a horizontal line, but this adjective is placed after a short, slanted, vertical line that points back to the subject. Thus, “Maggie is beautiful “would be diagrammed in this way.

Obviously, this short article does not cover every possible combination of words, but the six diagrams provided should give you a basic picture of how the eight parts of speech are used in the most common formats. Thus, even if you never become an architect or an engineer, at least you now know how to properly construct a sentence.

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Jim LaBate works as a writing specialist in The Writing Center at Hudson Valley Community College (HVCC) in Troy, New York.

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