"Who feels bad?" is generally reserved for asking who feels regret or remorse. It's not a typical way to ask who is feeling unwell. I'd really appreciate a German Mod (or someone fluent in both English and German) to clarify whether, "Wem geht es schlecht?" is enquiring after well-being or regret/remorse.
Thank you kindly. :0)
EDIT: As DanFelker wrote above, "Who is not doing well?" is one example for asking after someone's well-being. Another is, "Who isn't feeling well?"
So like you and many others in this thread I started out feeling convinced that "who is feeling badly" must be the more correct English grammar. However after looking into it a bit I realized there is a subtle exception to the adverb rules when it comes to a certain set of verbs which means we should drop the "ly"! This page explains it:
Rule: English grammar has one tricky caveat that seems like an exception to these easy rules: If the verb is one of these four senses—taste, smell, look, feel—don’t ask how. Instead, ask if the sense verb is used actively. If so, attach the -ly. If the sense verb is not used actively, which is more common, don’t attach -ly.
Roses smell sweet/sweetly. Do roses actively smell with noses? No, so no -ly.
The woman looked angry/angrily. Is the woman actively looking with eyes? No, only her appearance is being described.
She feels bad/badly about the news. She is not feeling with fingers so no -ly.
She feels bad/badly since burning her fingers. She feels with her fingers here so the adverb (-ly form) is used.
These aren't the only verbs that take adjectives instead of adverbs. In fact, all linking verbs do.
Be - The boy is hungry. Interestingly, the response "I am good" to "How are you?" is actually grammatically correct for this reason.
Seem - That book seems interesting.
Grow - I often grow tired after a long day at work.
Turn - The woman's face turned red from embarrassment.
A linking verb is a verb that connects the subject to additional information about it. Action verbs, however, describe actions that are carried out, and therefore must instead use adverbs. The only verbs in English that are always linking verbs are to be, to become, and to seem. Many other verbs (such as the ones you mentioned) can have different meanings to be either linking verbs or action verbs.
"Hear" takes adverbs and not adjectives (he hears well). This is because the examples of taste, smell, look, and feel don't actually refer to the senses, but the way they are perceived. "He smells well" means that he has a good sense of smell, but "He smells good" means that he has a good scent. The equivalent verb for the sense of sound is "sound," which is why "The music sounds good" is correct and not "The music sounds well."
The logical subject of the verb schlechtgehen (as with some other verbs which describe emotional or sensory states or changes) is in dative case:
Mir geht es gut. Ihm geht es schlecht.
If you ask about the person referring to said state, you need to use the interrogative pronoun in the corresponding form, here that'd be dative.
wer = nominative
wessen = genitive
wem = dative
wen = accusative
Brackenbury, although "bad" is not an adverb, in English it is often used in place of "badly"=Adverb. Source: https://www.oxfordlearnersdictionaries.com/definition/american_english/bad_3 "I feel bad" is a very common expression in colloquial English.
The verb "feel" is actually a linking verb in this case, and therefore it uses adjectives rather than adverbs. "I feel bad" is perfectly correct for this reason and not simply a colloquialism. The examples in the link you gave use action verbs, where "bad" is grammatically incorrect along with any other adjective.
Brackenbury, It's a little tricky in English. Feeling bad vs. feeling good is acceptable. Maybe because it describes one's state of being? "I feel badly" can be used in the context of regret-type situations (or if your feelers are malfunctioning) , but no one would say that when they have the flu. I think it's similar to looking and sounding. We (and things) look bad, sound bad, not badly.
In fact, though. 'feeling bad' is the correct grammar. 'Bad' is the adjective. It doesn't qualify your manner of feeling, but your state of being. Similarly, asked how you feel after a big success, you wouldn't say 'I feel proudly' but 'I feel proud'. If you're embarrassed at a big silly error, you 'feel stupid', not 'stupidly'. 'I feel badly' would only be grammatically correct if you wanted to say that you were really not very good at feeling - perhaps your fingers have gone numb, or you're really insensitive.
I did in fact use "feeling poorly" and it was rejected. That seems like an expression in American English at least that is regional or rural to some extent. I haven't heard anybody say that for 50 years, although my children accuse me of using obsolete slang.
"I'm sorry the missus is feeling poorly; here, I brought her some soup."
"I feel bad" is better in this case than "I feel badly/poorly." The verb "feel" is actually a linking verb here, so it takes adjectives instead of adverbs. "I feel badly" would mean that the speaker isn't good at feeling for one reason or another.
@Harroghty I can't reply directly to your comment, but "I feel badly" isn't accepted because it is incorrect for the reasons given above. "I feel bad" is grammatically correct and should be both accepted and demanded.
"Who is not doing well" was not accepted, and it conveys the same sense as "Who is feeling BADLY" but DL's answer, "Who is feeling BAD" does NOT convey the same the same sense as "Who is feeling BADLY." Feeling badly tells HOW you are feeling. Feeling bad tells WHAT you are feeling. I feel bad, I think I'll break a window. Like the difference between feeling "poor" and feeling "poorly." C'mon DL, you're better than this.