(More advantages of not using T-9: (1) you don't have to look at the screen to choose words, meaning that you can, in theory, text blind whilst walking down the street, and (2) in making the semicolon difficult to get to, T-9 is probably doing a grave injury to English punctuation. Disadvantages: it's slower, at first.)
How do you text on your phone?
Letter by letter, mostly in normal English
LTR BY LTR, W.ABBREVS
using the automatic dictionary/autocompletion feature
I don't have a mobile phone/I don't text