"Worüber Mittwoch?" is not just wrong, Germans would even not understand it, if they would not know you being English and translate in re-translate it from German to English and backwards.
Generally the vocabulary "What...about?=Worüber...?" is correct.
What do you talk about?=Worüber sprichst du?
What is the text about?=Worüber geht es in dem Text? Wovon handelt der Text? (Worüber ist der Text? is bad German, but ok.)
But "What about X?" has (for Germans) nothing to do with this meaning of "What...about?". "What about X?" means "Was ist mit X?"
I would propose that any question started with "Worüber" needs a verb. Even if the verb is clear from and used in a sentence before, I would not waive it (e.g. "Worüber schreibt ihr? - Ich schreibe über Bäume und Leon (schreibt) über Flüsse. Und du?/Und worüber schreibst du?". "Und worüber du?" is unusual, just ok, but only in this context.).
Things like "Warum (nicht) Mittwoch?=Why not Wednesday?" are different. But for "What about X?" we say "Was ist/wäre mit X?", nothing with "über" or "worüber".
I came across this thread and was wondering if you could verify something for me. This is an old post so I'm just throwing this out there. I know you can't say "Worüber Mittwoch?" by istelf. But if you asked someone which day is their favorite and they reply with "Mittwoch," could you then say "Worüber magst du Mittwoch?" (What about Wednesday do you like?"
"What is with Wednesday" is accepted as a translation - but this only makes sense as a complaint. Same with other similar sentences about people, "What is with him" etc. Can these be understood as complaints in German, or do they actually always mean "What about X?" as in "How about X?". Since "What about X?" can also mean "What would you like to know about X?" or "What did you say about X?" and probably some others, it would be really useful to get a clear context for when this sentence would be used.
You are correct that all good English sentences require at least one verb. However, in conversation we frequently use fragments and incomplete sentences. "What about ...." introduces a suggestion, a soution, an idea for consideration into a conversation. Someone says, "I need another person to help with my project." Someone answers, "What about Anne? She is so enthusiastic." Or, two people are looking at their schedules trying to find an afternoon to do something together. "I am busy Monday, and you work Tuesday. What about Wednesday?..." This could be also expressed with "and......?" "I am busy Monday, you work on Tuesday, and Wednesday....? Spoken English can use even shorter fragments. For example, "Monday, no. Tuesday, no. And Wednesday?....hmm, maybe, maybe not." (No verb is used).
Some people use "How about..." instead of "What about..." I am an American, and locally, here in Virginia, you would hear this pronounced with just two syllables, "How 'bout..." Example: "You don't want coffee? well... how 'bout some tea or hot chocolate?"
By the way, your second statement, Jussel11, is also missing a verb. "In English as well." does not contain a verb, but in the context of your discussion, I knew that you meant, "This is true in German as well as in English." So, my question is, do German speakers also use verb-less fragments when speaking?
So, my question is, do German speakers also use verb-less fragments when speaking?
Yes, we do.
"I am busy Monday, you work on Tuesday, and Wednesday....?" - "(Am) Montag habe ich zu tun, (am) Dienstag musst du arbeiten, und Mittwoch?"
"Monday, no. Tuesday, no. And Wednesday?....hmm, maybe, maybe not." - "Montag: nö, Dienstag: nö. (und) Mittwoch? ...hmm, vielleicht, vielleicht nicht." (Also no verb is used).
That sounds natural to me.
I think it was a poor explanation of mine. But there is not really a better one: It is just to learn like vocabulary:
'What about X?' = "Was ist mit X?", "Und X?"
While every word (including "ist") is necessary.
Spoken it can sound like "Wasis mit X?"
By the way: How can "What about X?" be turned into an whole sentence? Would it be "What is about X?" ?
Thank you, Jussel11, for your thoughtful answer. I will try to answer your question.
"By the way: How can "What about X?" be turned into an whole sentence? Would it be "What is about X?" ?"
This does make me smile because, believe it or not, adding the words "is it" to the idiom "What about X? changes the meaning in English. I believe "What do you think about X?" preserves the meaning. This works in a conversation to give a suggestion. "What do you think about Wednesday? Will it fit into your schedule?"
Adding "is it", examples :"What is it about Wednesday?" , "What is it about this town?" , "What is it about Anna?" indicates that the day or place or person is special in some way. This may be a negative or positive comment, and is almost always followed by an explanation. "What is it about this chocolate? I can't stop eating it!" "What is it about this town? Everyone is so rude." "What is it about Wednesday? It is the one day I am always in bad traffic." "What is it about this mountain? I feel so peaceful here." Also, in English the word "it" in all the above examples is absolutely required. We cannot say "What is about X?" although we can say "What about X?" I guess, if the verb is included the subject must be stated.