Stan Carey on the vocative comma

Editor and “swivel-chair linguist” Stan Carey explains the uses of the vocative comma: “Hello, vocative comma” (Macmillan Dictionary Blog).

After reading this column, I realized that I’ve been undermining the vocative comma for the past fifteen years. My post about how to e-mail a professor recommends beginning (in the absence of other instruction) with “Hi/Hello Professor [Blank].” No vocative comma. But as Carey’s column says, “In informal or unedited ­writing, the vocative comma is often skipped.”

I think that e-mail tends toward informality, enough so to omit the vocative comma. But not enough so to begin with, say, “Hey.”