heh, my native language doesn’t distinguish between lax and tense vowels though. That might be the main reason for that — I learned English from a kind of midwest-west coast accent (idk, Arizona) mixed with RP and Thai and like some south asian variety. So my pronunciations are all over the place, but I do try to stick to standard AmE.
Incidentally, I don’t actually use /ʃ/ (or its affricate or their voiced counterparts) for the sh, ch sounds — I use the alveolo-palatals (ex. /ɕ/) instead, because they’re closer to what I have in Thai :>
It just so happens that Japanese also uses these more frontal (I think?) consonants instead too, so my Japanese accent sounds less western (ig, lol). Interestingly nobody’s ever said anything about that particular variation — I suspect that’s mostly because English doesn’t distingush between postalveolars and alveolo-palatals.
Funny, I’m trying to learn Polish right now and I can’t distinguish between the retroflex (ex., /ʂ/) and the alveolo-palatals, which is apparently a distinction that it makes
I just don’t understand retroflex consonants.
Your point about how a long-lax /ʃɪːt/ is a stretched-out “shit” and how a short-tense /ʃit/ is a quick “sheet”… I almost see the opposite way, hah. For me /ʃɪːt/ is just “sheet”, and /ʃit/ is just “shit”. Interesting how that comes about!