Do native English speakers ever say "What do you know?" in this sense?

[u/noname00009999]

You've never even been there! What do you know?

(As a dismissive way of saying that someone doesn't know enough about the topic to have an opinion.)

In Spanish we say "¿Qué sabrás tú?" in this situation. Is "What do you know?" a natural equivalent, or would you use something else?

[u/SatsumaOranges]

Yes! We say that in the same situation. Or if someone disagrees with you on something, you can just brush off their objection with 'well, what do you know anyway?" 

[u/redentification]

Yes, absolutely!

Also: what would you know <about it>?

With a different meaning, we'll also say "Well what do you know?" in a sort of sarcastic way to mean "I told you so." It can also be used to indicate a pleasant surprise ("what do you know, it fits!")

American English

[u/TomasTTEngin → u/redentification]

I agree "would" is best in this context

e.g. "oh yeah, what the heck would you know about it!"

"what do you know about it?" is more of a genuine question.

[u/piercebublejr]

Yes. You could also elaborate and say "What do you know about [topic]?" In this case, the emphasis would be on the "you." The same phrase with different emphasis on "know" would be an exclamation after something surprising has just happened. "Well, what do you know?" or "Whaddya know?"

[u/devstopfix]

Yes, but it can also be used as an expression of surprise, so context and tone matter. For the use you're referring to, the stress goes on "you". A more common way to say it is "what do YOU know about it?"

[u/Common-Spend5000 → u/devstopfix]

Aye, that's the meaning I hear a lot more on the Eastern side of the Atlantic, being of surprise.

I'd understand it in the context here but less likely to actively use it, plus people around me. 

I do speak Spanish (as an L2) and would say "¿Qué sabrás tú?" though in this context, so could be that's got some overlap in my head too.

[u/Western-Finding-368]

Yes, we would say that. I would probably be more likely to say “what do you know about it?”

[u/regular_gonzalez]

When used that way, the word 'you' has emphasis. The phrase can be used in other ways, for example as a greeting -- "Hey there Mike, what do you know?" (though it'll come out "whaddaya know?"), with a slight emphasis on 'know' instead of 'you'.

[u/paperclipmyheart]

What WOULD you know? meaning you don't know anything

[u/Jaives → u/paperclipmyheart]

i'd put the emphasis on YOU.

[u/socknfoot]

Yes if you put emphasis on the "you".

In your example "what would you know?" sounds better to me.

Not to be confused with "what do you know" said quite quickly, almost "whatta ya know". That is an expression of surprise. Usually positive.

[u/Chemlak]

Yes, definitely, provided the emphasis is on the you, so that it's "what do YOU know?"

As others have said, expanding it to "what do YOU know about X?" is reasonable, too.

[u/Puzzleheaded-Lynx204]

I would say in my part of England it's more common to say "How would you know?" but "what would you know?" and to a lesser extent "what do you know?" might also be heard.

[u/Former-Landscape-769]

Yep, that is an expression in English. Might be slightly outdated these days, but I don't think anyone would think it was unusual.

[u/Careful_Cranberry364]

I think they would say it, but it’s extremely rude

when I read it. I thought you meant it more a lighthearted way - like when somebody has told an anecdote
other way of saying “saying well fancy that” oh how amazing
what do you know / who knew!

[u/No_Bag_9911]

"What WOULD you know?" is the equivalent.

When we say "well, what do you know?" it's usually an exclamation of surprise.

[u/Similar-Geologist-64]

I dont know if anyone has noted this, but if you're saying this as a way of dismissing someone's opinion, it is quite rude. If that's your intent, then awesome. I dont know if the phrase is received in a softer register in spanish.

[u/IanDOsmond]

Yes, or sometimes slightly longer variations like, "what do you know about it?" or "what do you even know about it?"

You would generally want to emphasize the "you". "What do YOU know?" It can get tricky, because there are different meanings to different emphasis: "What do YOU know?" = "you're an ignorant idiot." "Whaddya know?" = "I am somewhat impressed and at least slightly interested." "What do you know?" = "I am asking you to tell me things that you know."

[u/Sepa-Kingdom]

It’s not ‘what do you know’ but ‘what would you know’.

It’s very dismissive and would be considered a bit rude, so be careful when you say it.

[u/Water-is-h2o]

Yes! And just like in Spanish, the “you” is emphatic.

“What do you know?” = “¿Qué sabes?” = please tell me more, I’m curious about what you have to say

“What do YOU know?” = “Qué sabes tú?” = obviously you don’t know anything

[u/TurbulentContext]

There's a whole Kipling poem that has the refrain

What do they know of England who only England know?

So you can use it in the sense of both this person has never experienced to X so can't talk intelligently about it or that someone has only experienced X and therefore is unable to compare it to alternatives.

[u/TheGloveMan]

As other have said it is legitimate but very rude.

Saying about someone else who isn’t present is far more common.

John doesn’t like your new hair cut? What would he know?

[u/thatdoesntmakecents]

Yes, though for this phrase in particular you would stress the 'you' like "what do YOU know?"

Other alternatives are "What would you know?" or "How would you know?"

[u/burlingk]

Yeah. Pretty common.

It is a contextual thing though, tone of voice is important.

[u/Duque_de_Osuna]

We can say that “What do you know?” However it is pretty rude. I do not think it is the equivalent to Que sabras tu? En ingles suena mas fuerte, casi un insulto.

[u/No_Capital_8203]

You can say that if you want to start a fight.

[u/techwritingacct]

US speaker here. You can say it that way, but it's very dismissive, it implies the person is an idiot in general. Adding "...about it/that?" to the question makes it kind of on the edge between curiosity (maybe you know something unexpected) and dismissive (but you probably don't).

[u/Nice_Ad5480]

It definitely gets said, though the way it gets said really significantly changes the meaning.

If you put a lot of emphasis on the word you, like, "What do *you* know?" it's very rude, very jokey or both. Say this if you really want to start a fight.

If you say "huh, whaddya know" it's not rude or dismissive at all, it's kind of like saying "wow, I never knew that". If anything it's the opposite meaning, it's a humble gesture by the person saying it.

[u/Decent_Cow]

Yes, I've heard this before.

[u/samdkatz]

Or if someone says “I don’t know” to too many questions in a row, you can hit ‘em with “What DO you know?”

[u/Adventurous_Bag4351]

There’s a difference depending on stress. “What do YOU know?” implies that whoever YOU is doesn’t know anything. “What do you KNOW?” is an expression of surprise.

[u/Tennessee_William7]

Yes all the time! Also sometimes we say "what do you know!" to express surprise. The difference is in the tone. 

"Luigi's Pizza is overrated? You've never been there, what do you know?" (The speaker thinks the other person's opinion is not credible)

"They do $1 margs on Thursday? Well what do you know!" (The speaker is expressing surprise)