Among its six uses, the appendage comma separates interjections from the main thought of a sentence.

Interjections are abrupt words and phrases that express emotion or signal for attention. English has collected many interjections over the years. Here are some:

When an interjection communicates a strong emotion, it typically uses an exclamation point to match its emphasis. For example: “Wow! That was epic.” Interjections that express less emphasis use the appendage comma, instead:

And these mild interjections use an appendage comma pair when they occur in the midst of a sentence:

For the use of interjections with names, review the vocative comma page.

Interjections also require the appendage comma when they’re used as verbal pauses. Verbal pauses rarely occur in formal writing. But they make regular appearances in creative writing, emails, and text messages: