If you’re the least bit tech savvy, you probably know the meaning of — and maybe even use — a few texting acronyms, like OMG (oh my God), LOL (laugh out loud), or even TTYL (talk to you later) or IDK (I don’t know).

But if you have teens, you may want to bone up on a few more, like IPN, LH6, IWSN, GNOC, and P911. That last one means “parent alert” and the rest are texting lingo for a few things you definitely want to be alert about.

The Pew Internet and American Life Project, a survey of 802 parents and 802 kids between 12 and 17, found that cell phone texting is the preferred method of communication for tweens and teens. Fifty-four percent say they text friends daily and one in three sends 100 texts a day. Some are using abbreviations designed not just to save typing but to hide information from prying adult eyes.

Related: 7 Ways to Prevent Your Teen From Texting and Driving

That information isn’t always what you think it is. “It doesn’t necessarily have to be alarming,” says Denise DeRosa, program manager for Good Digital Parenting, part of the Family Online Safety Institute.

“A kid might text PIR (parent in room) so their friend won’t discuss what boy you like. Overwhelmingly kids are probably using their phones the way we use our phones — to set a time to meet at the mall, talk about what movie they want to see, what they want to do after school — only they’re more inclined to text rather than talk.”

In fact, although sexting gets a lot of press, it really isn’t common. While 83 percent of kids use their phones as cameras, only 4 percent have sent nude or partially nude images, according to the Pew research. But there’s always a danger that tech-smart kids aren’t so smart about the real world: About 30 percent of teens meet “friends” they’ve met online in real life, found a study published in the journal Pediatrics. About 10 percent of the time, those encounters involve sexual overtures or intimidation, the study revealed.

Have the safe text talk

To help you keep your kid safe on his or her smartphones, have a discussion about what’s appropriate and not appropriate phone use, says DeRosa. “Point out that since you’ve given them the phone in the first place, you trust them. Tell them you know that this kind of [shorthand] communication happens and that you’re going to check up on them periodically. And if you see that they’re using the phone appropriately, there will be a lot fewer check-ins.”

Related: 7 Ways to Keep Your Kids Safe Online

It also helps to know the more alarming acronyms even if, as DeRosa points out, they change the minute parents start figuring them out. Here’s a Rosetta Stone for some of the more common ones.

(To find out more, check out netlingo.com and the website of the NetSmartz, a program of the National Center for Missing and Exploited Children.)

8 Oral sex
143 I love you
420 Marijuana
1174 Invited to a wild party
AMEZRU I am easy, are you?
ASL Age/sex/location
CU46 See you for sex
F2f Face to face
GNOC Get nude on camera
IPN I’m posting naked
IRL In real life
IWSN I want sex now
KPC Keep parents clueless
LH6 Let’s have sex
LMIRL Let’s meet in real life
P911 My parents are coming
PAL Parents are listening
PAW Parents are watching
POS Parents over shoulder or piece of s---
RUH Are you horny?
RU/18 Are you over 18?
TDTM Talk dirty to me
WTGP Want to go private?
WTTP Want to trade pictures?
WYRN What’s your real name?

Denise Foley is a veteran health writer and a former contributing executive editor at Prevention magazine.