Teenage American girls send more than 100 text messages a day, according to research from the Pew Internet and American Life Project.
It makes texting the most popular method of communication amongst young people - beating not just phone calls and social networks, but face to face communication too.
In February 2008, 38 percent of teens texted friends daily. But just 18 months later that figure had hit 54 percent.
Half of teens send 50 or more text messages a day, and one in three sends more than 100. Girls aged 14 to 17 are the most voluble, averaging 100 messages a day. The youngest teen boys are the most uncommunicative, averaging 20 messages per day.
Text messaging has become the primary way that teens reach their friends, surpassing face-to-face, email, instant messaging and voice calling as the go-to daily communication tool for this age group.
But most still use voice calling as their preferred mode for reaching parents.
The results show that teens aren't taking a blind bit of notice of school rules. More than two thirds of those who say their school has a blanket ban on cellphones take theirs in anyway, and a similar number say they have texted in class.
A quarter have actually made or received a phone call in class, which doesn't say much for teachers' powers of observation.
Half the 16 and 17 year olds said they'd texted while driving.
But 'sexting' isn't necessarily the problem that some make out, with just four percent of teens saying they've sent a sexually suggestive nude or nearly nude picture of themselves via a text.
Of course, the teens are using their cellphones for a lot else besides simply chatting. Nearly half play games, a third exchange videos, and 83 percent take pictures.
The full study is here.