Txtspeak
Txtspeak (or "textspeak", or more prosaically, "SMS language") is the variant of written language used in text messaging, or sometimes in similar media such as Twitter, chat rooms, and so on. It is marked by much use of abbreviation, including "u" for "you". It arose as a practical technique to express messages concisely in the face of character limits and difficult entry of text on pre-smartphone buttons, but in some circles could be used to tell "insiders" from "outsiders" in a particular community by what sort of texting style they used. It also became popular for commentators to decry the alleged death of the English language due to "degraded" usage by young people. But other groups, including businesspeople, have forms of jargon that are sometimes decried too.
Now, if you get the trendy "Yo!" app, you don't even need to come up with any Txtspeak yourself!