PPs have listed the months when the large South American teen groups come in force ( multiple tour groups at the same time). But they come sporadically, in smaller total numbers at other times as well. They most frequently stay at the value resorts, but occasionally stay at some of the mods. Any group, no matter where they're from, can get discounts if they have sufficient numbers. I haven't heard of the teen groups staying deluxe, but wouldnt be surprised to hear of some adult or family groups ( who rarely create problems) staying there.
We've encountered some of these groups, who have behaved abysmally, several times. One of the main reasons we no longer will visit in Jan. But we have seen equally or worse behavior by groups of American cheerleaders and other youth groups. So I won't single out the SAs for bad behavior. They should all receive the same consequences for their behavior. Unfortunately I have rarely seen Disney take any action to correct it. The recent rumors of a Disney directive to curtail chanting is, I suspect, going to remain largely unenforced.