Earlier quoted context omitted.
"The letter people" You mean LGBT+? Because dang that's an incredibly insulting way to completely dismiss everyone who isn't straight then
No, I mean the people who identify as a letter and scald you if you don't know what their letter means. I have no idea what half of those letters mean or whether it means gay or straight (the T could definitely be straight, I know that much). I've also known plenty of gay people over the years who haven't ever mentioned these letters so it's nothing to do with that.
L: Lesbian (This means women who like women.)
G: Gay (This means men who like men.)
B: Bisexual. This means women and men who like both women and men.
T: Trans. This means you do not identify with the gender you were assigned at birth.
Q: Queer. This means you do not identify as straight but don't feel like you necessarily fit into just one of the other buckets all of the time. Maybe you don't feel particularly like a man or a woman, or you don't feel like masculinity or femininity really even come into play in your sexuality.
I: Intersex. Some people are born with sex organs that don't look like the venerable "man/woman" anatomy charts. As it turns out they are still living breathing people.
A: Asexual. Some people do not feel sexual attraction toward other human beings. As it turns out they are still living breathing people.
+: Sometimes people feel like they fall somewhere on a spectrum of the above. Sometimes people using the acronym intend to include allies. Sometimes people just haven't figured out their sexuality yet exactly, they just know 'one man and one woman' isn't it.
LGBTQIA+. It's not alphabet soup, it's not a joke, appending BBQ isn't clever. It's just lesbians, gay men, bi people, trans people, queer people, intersex people, asexual people, and allies or people who are still having trouble categorizing themselves and how they feel.
Now you know all the letters. It didn't even use up the whole alphabet.