i think you're on to something. when i tell people i like sports, their jaws usually drop. i grew up playing basketball and soccer, and it just so happens that i know as much about nba basketball as some of my other areas of expertise like new american cuisine, typology, post-punk, and post-structuralism. but it's shocking to people nonetheless.
language shifts with mood. at times i am very subdued and very curt, and if i'm in a larger setting i'll keep it shorter. we still have a way with groups where we kind of let some of our humor show in odd quirky ways, responding to the situation and our own ideas/interpretations visibly. if i'm with one other person, i'll start writing more freely and everything sounds like an artful letter from one of those poets you hear about in school.
our communication is always a bit tight and controlled, unless we're in a really really really secure space. i've only ever felt this with one or two people. we definitely can get much more loosey goosey in the hips of our words when we feel extra frisky. i use this analogy a lot, but watch a jonathan richman video, and then imagine instead of a crowd it is for one person. bc with more the shameful display would be tooooooo much!
there's a theory that your 7th function is your deceiving/funnybone. for infj it would be Te, for intj it would be Fe. this is probably why i enjoy bantering with intjs humor-wise more than any other type, with entp close second. we both know how to play it up, while still creating complex Ni tripwires EVERYWHERE and fondling them oddly in public. think demetri martin, whose tv show isn't that great (tho creative!), but his standup is, in the words of nba commercials, fannnnntastic!
we have cluttered heads and some find that charming. when we play the imagination game we can keep anyone on their toes, literally gasping for breath. with S types we are operating at about 40% of our fun potential, and the air feels smoggy.
also: Te goes for crass and Fe goes for playin' it up all ridiculously, overdoing it, etc. we learn from each other tho, and pretty soon can do either with equal deftness. the thomson book says that injs have good access and easily learn how to use the other half of the Fe/Te schism in development. who knows?