Why Periods Are Like Brake Lights

Recently, it occurred to me that punctuation symbols in written English are a lot like brake and turn signals in a car. Students sometimes wonder why teachers care so much about periods and commas, but in English, they act like car lights … they help the reader know where you, the writer, are going. We often get annoyed by drivers who don’t use signals because they take us by surprise; suddenly, they do something that we don’t expect. Think of periods as brake lights and commas as turn signals, and then you will understand better how they help your reader.