The first letter of a text or instant message is the most important. Never mind the actual meaning of the words it introduces; the mere keystroke is a starter pistol. Once you’re off, you need to complete your message quickly. That’s because most chat clients let you know when your partner is typing a message. And the longer this message takes to type, the more you start to worry: Is it going to be confrontational, confessional, or emotionally challenging in some other way?

Awkward silence has an analogue online, thanks to the typing alerts that linguists call “awareness indicators.” On Google Talk or Gchat, a prompt says “Ben is typing…”; on Apple’s iChat a plain ellipsis signifies the same. These features are not as disposable as they may seem. One of the Internet's most remarkable effects on language is the jury-rigging of writing for conversation. In lieu of facial expressions, we type emoticons and emoji; for tone and inflection, we make novel use of punctuation. The typing awareness indicator is another adaptation: a way to pace a written conversation. But it can do more than just indicate awareness. It can induce anxiety, too.

“I’ve been in a few situations where I'm chatting with someone and I start typing a reply, but then stop before I'm finished with the reply,” Clive Thompson, author of Smarter Than You Think: How Technology Is Changing Our Minds for the Better, wrote me by email:

Maybe I'm rethinking what I'm writing before hitting "send", or maybe I'm temporarily pulled away by something else like a phone call. But I'm aware that the person on the other end may have *seen* me start typing and then stop—so I'm aware they may be wondering exactly what's going on in my head. I've been in the other situation, too, wondering: Hmmm, why did they start typing and then stop? Obviously, most of the time this isn't an issue, but if you're involved in a sensitive or emotionally charged conversation, these questions of pausing can become emotionally charged themselves!

One of writing’s traditional advantages over speech is the time it affords you to collect your thoughts. This time empowers you to calculate your words’ effects on their reader. Rather than blurting out “YOU’RE SO HOT,” you pen a pleasing phrase: “Shall I compare thee to a summer's day?”

Text and instant messages, however, are eroding this advantage. We don’t correspond over text and instant messages, like we do in letters; we chat in quick informal exchanges, like we do face-to-face. And one of the underpinnings of spoken conversation is what's known in linguistics as turn-taking. “We need some way of determining when someone else's turn is over and ours can begin,” says Deborah Tannen, a professor of linguistics at Georgetown and author of You Just Don't Understand. “In speaking, we sense whether others are done—their voices trail off, their intonation goes down, they seem to have finished making a point, they leave a pause to let us know they're finished.”