One simple aspect of English is that you can just say: one car; two shirts; three dogs. In Thai, each noun has it's own quantifier, the word that must be used with the number to express any quantity of something.
I love pakawma, the table-cloth looking general accessory of the country folk. They make a good scarf; sweat-mop; hat; towell; or single wrap-around garment for on the way to the shower. I like the hand-made ones from the deep countryside. They are beautiful and cheap. I own about forty of them, so far. I bought three more on this trip, two bucks each.
But I always forget the quantifier. It's puhn, as in pakawma, (two) puhn. If you just say (two) pakawma, people just look at you funny.
These things can be devilishly weird. Like for most animals, it's doo-ah, as in (dog) (two) doo-ah. But elephants have their own word, so for elephants it's (elephant) (two) chuak. Incidentally, shirts are also doo-ah, like the animals, except the elephants.
For fruit, it's luk, as in (apple) (one) luk. But bananas are different, that would be (banana) (one) pohn. That's because bananas are always "of a group," and one (or more) of a group of anything is pohn.
Two stores is (store) (two) rahn, but that's only if they occupy part of a building. If the stores are actually their own free-standing buildings, it's (store) (two) lang.
At the outside of weird are mobiles, those cute hanging things. If the mobiles are flat, like hanging from a straight bar, it's (mobile) (two) paeng; if the mobiles are round, like hanging from a circle, it's (mobile) (two) poo-ang.
To be fair, there are really only two hundred and seventy or so distinct quantifiers, so it could be worse. But it's bad enough if you happen to be the student.