Let's just begin with: Never. Ever. Under any circumstances, use text language unless you are producing a character's text messages.
Wrong Example: OMG Tyler is 2 die 4!!!!! he is gr8 at everything i want 2 pinch his cheeks!!!!!!
Right example: oh my gosh, Tyler is to die for! He is great at everything I want to pinch his cheeks!
Right example 2: I showed Milo her text. OMG Tyler is 2 die 4!!!!! He is gr8 at everything i want 2 pinch his cheeks!!!!!!
Writing like this signals laziness and care free writing, meaning work is not being put into a user's works.