i do see personality in typing style but not as the op describes it
txt speech like this is rly casual and u only rly do it when u hate the keyboard or are typin w/ 1 finger/a finger from the hand holdin the phone
this sort of speech where I maintain conventional grammar and spelling after the first word (but still minimal unnecessary punctuation) is also pretty common in casual contexts. periods are used to mark sentence ends only where it's not obvious. I generally alternate between this and nocaps as described in the last example
This is almost identical to the above layout but it's more tied to mobile platforms that automatically capitalize for you, like a smartphone. People might be capitalizing intentionally though
there's also this format which is like the above two but with absolutely no capitalization. it's very casual but i wouldn't really call it outright lazy like txt speech
