Homeschooling Importance of Learning to Diagram Sentences

Diagramming sentences may seem like an activity from the 1970’s that may be irrelevant today, but the fact is that diagramming sentences teaching students about the way words in a sentence function together like no other method. Diagramming sentences is a visual method of teaching grammar that allows students to see the relationship of the words.

Teaches subjects and verbs

The most central aspect of diagramming sentences is the subject and the verb. The basic first construction of the diagram is a plus sign basically that divides the simple subject on the left side and the simple predicate or the verb on the right side. Even if you never get past the basic subject verb diagram, it will reinforce the teaching of these two components.


Often students have a difficulty determining the words that describe nouns or adjectives. The diagram format can help students to determine adjectives. You can easily lay out a diagram for a student. In a basic sentence there could be a couple adjectives to describe the noun. In the sentence “The big black dog barked.” The diagram will have three slanted lines drawn off of the subject. The student can visually see that it is necessary to look for three adjectives in the sentences. Eventually the student can create his or her own diagrams which will then demonstrate their knowledge of adjectives.


One of the toughest parts of speech for students to determine is the adverb. By using diagrams, students can begin with diagrams with adverbs describing verbs. Then it can be increased to describe adjectives and then other adverbs.  In the example sentence “The big black dog barked loudly.” There would be one slanted line beneath the verb barked. By adding the step it is easy for students to visualize that the adverb “loudly” described “barked”.


Diagrams teach students how prepositional phrases relate to the other words in the sentence. It is often difficult to determine what the prepositional phrase describes. In the example sentence “The big black dog barked loudly in the night.” The prepositional phrase “in the night” describes “barked” as it tells when the dog barked.


Using the diagramming method of teaching grammar, will allow students to have a visual way of teaching compound elements.  Depending on the grammatical element, the item will divide and it will have a place for a conjunction usually on a dotted line that connects the two elements of the compound area.  With the example sentence “Bob and Susie sang.”  The two subjects each have their own line parallel to each other and then combining to a V pointing to where the division takes place to divide subject and predicate. If there is a compound verb it is a reverse V formation with the verb blanks running parallel. It becomes more complex with the compound adverbs and adjectives.

Using the device of teaching grammar by diagramming sentences, one can allow students to see the relationship between words in a sentence. It allows the student to be guided at first by pre-made diagrams and then is followed by allowing the student to take a sentence and create the diagrams by themselves.