I wonder if Duo would accept "That is probably a hoax?", because "Det er vist en and?" is what Danes would say about a false, or doubtful article in a newspaper.
Wow, that's what it is in Hungarian, too! Does anyone know the origin of this?
According to (German, because we use that expression, too) Wikipedia, the origin is unclear, but it probably comes from the French "donner de canards" - "to give ducks", which means "to lie". Why that is, no one really knows, though. Says that the duck may have been assumed to be an unreliable brooder.
Because, in English at least, something can be said in that tone with a question mark to show that it was a questionable question.
So this would be (again, in English at least) the answer to "What is that?"
Idiot: "What is that?"
Sarcastic person: "Erm, that's probably a duck?"
I would put a question mark to express uncertainty in the statement. As in, that is probably a duck, but I am not really sure.
I feel 'it is probably a duck?' is grammatcally incorrect' but you could say 'it is perhaps a duck?'. Probably carries a greater degree of certainty, making it sound stilted in this context?
That's a little odd, then, because vist means "surely, certainly", which is an even greater degree of certainty. :)
This Danish sentence sounds like "I don't doubt this is a duck. ... Isn't it?"
I would say that it could be used as you suggest, but it will then be more making a conclusion than a suggestion.
Joseph Bevis: Actually you can also hear that the voice poses a question, because the last word is high in pitch.
Because this is not a.. do you say "interrogative question"? It's not a standard question where the subject and object are inverted. That would be "Er det vist en and?", like in English.
Although vist wouldn't really fit here if you're unsure what it is. Måske would be better.