Standard English? Obviously not.

A lot of people think they speak better English than I do because they are white.

What, am I wrong?

I speak Standard American English. Not that I care to. But, when called upon to invoke that prestigious, artificial, and soul-less dialect, I do it. And I do it well.

Also, I have a BA and MA in Linguistics, so the chances are that I am more aware of SAE grammar than you.

Pay attention.

BAD: Noun (the good, the bad, and the ugly)

BAD: Adjective (this rice is bad)

BADLY: Adverb of manner (you dance badly); incompetent.

BAD: Adverb of intensity, negative aspect (he's bleeding pretty bad)

I SAID PAY ATTENTION.

When you use the copular verb to be and you want to describe the subject with a predicate noun, you use the adjective:
You are bad at dancing.

Note the impossible alternative:
You are badly* at dancing.

Verbs of sense stimuli (to look, to sound, to feel, to taste, to smell) behave like copular verbs.
You smell bad. You look bad. You sound bad. I feel bad.

When paired with the -ly version, they describe MANNER, children.
You smell badly.

Read: "your sense of smell is below average"; or "you perform the action of smelling in an improper manner." Yes, it is grammatically possible, but it has a different meaning than "you smell bad."

Don't believe me? You are a victim. You are a victim of English teachers who overgeneralized the -ly marker of adverbs.

"In English, adverbs are marked with -ly. This is a descriptive statement. Most regularly-formed adverbs are, indeed, marked with -ly.

BUT NOT ALL.

What, do you want examples? Please!
It is very easy to provide tons of non "-ly" adverbs. I can do that no problem. I bet you could, too, if you thought hard enough. What's wrong? Am I going too fast for you? I guess you were dead wrong about the whole adverb thing. Don't worry, you'll do just fine in life. Nobody will ever call your grammar into question.

Maybe you say things like:
I feel badly about the whole situation.

And maybe you say it because you think it sounds smart. Fine. It's a free country and heaven knows I'm not a dialect snob.

But don't pretend it's Standard English to talk that way, because obviously it's not. And don't correct my grammar, chuck; your white priviledge doesn't apply.