Even on college campuses, anyone in doubt need only pick up a copy of the student newspaper.
Typically a college freshman is required to pass an English test and take remedial classes if he/she fails. Same for math, but that's a whole 'nother story.
Small children often put "-ed" at the end of a strong verb, like "I eated a cookie". If nearby adults speak correct English, the children will eventually learn which verbs need a vowel change.
Some verbs can form the simple past tense in more than one way, like dreamt/dreamed or hung/hanged. ("hanged" is archaic but occurs in legalese: "hanged by the neck until dead".)
What was wrong yesterday is sometimes correct today, and what is wrong today may become correct tomorrow. As a dinosaur, I cringe when I hear "this data" in place of "these data", "different than" in place of "different from", or "I'm like" in place of "I said".
To me, "shall" often denotes obligation, and "will" often denotes volition. That's why "shall I open the door?" does not mean the same thing as "will I open the door?" Youngsters will cringe at either statement; I would cringe only at the latter statement, which sounds like a demand for a prediction. "Shall", "will", and other modals are also helper verbs, like "be" and "have", but with different syntax.
American grammar and spelling are different from British grammar and spelling. After all, we are divided by a common language.
Spelling bees depend on the preconception that there is one and only one correct way to spell a given word. This is widely believed to be true for most English words, although the "correct" spelling may depend on your geographical location.