"Do we have a radio?"
Translation:Onko meillä radiota?
I guess it does depend on that. I don't know a rule for when it should be nominative and when it should be partitive in a question, but as a native speaker I could imagine saying "onko meillä radiota?" when I don't know what the answer could be, and I would be more likely to say "onko meillä radio?" if I'm surprised to see or hear a radio that I didn't think existed, expecting a positive answer since I now know that it exists.
I don't think that's a rule. Whether partitive case should be applied to a noun is not influenced by whether or not it has an adjective, and the same case should be applied to both the adjective and the noun, for example "onko meillä hyvää radiota?" (or colloquially "onko meillä hyvää radioo?")
I agree. I have looked in my copy of "Suomen kielioppia ulkomaalaisille" (by Leila White), and it says: "kysyvässä omistuslauseessa on usein partitiivi". Sadly, there is no explanation.
White has a few examples: "Onko sinulla siskoa tai veljeä", "Onko sinulla puhelinta", "Onko sinulla sanakirjaa". Interestingly, she has a counterexample: "Onko sinulla auto vai vene".
I think it's basically what Kristian described above: If there is doubt or it's less likely to be true, you use partitive. If it is more likely, or definitely true as in the case of having found the radio, you use nominative.
In your examples, the three first ones mean you really don't know what the answer will be. The last one means you are pretty sure the responder has either a car or a boat. Onko sinulla autoa tai venettä? is a possible sentence as well, but shows you are much less certain about the responder having either.
Usually, the context guides you in which one sounds more natural. That's why these are so hard on Duolingo, where there is no context.
Annika has it right. There are two or-words in Finnish, tai and vai.
Onko sinulla siskoa tai veljeä? : the questioner has no knowledge of the questionee's siblings up to the point whether the questionee has any at all
Onko sinulla sisko vai veli? : the questioner already knows that the questionee has either one and now want to get more specific info
These coordinating conjunctions can also be used to show exclusivity.
- Otatko kahvia tai teetä? : the questionee has an option to select something else, e.g. juice
- Otatko kahvia vai teetä? : the questionee must choose between those two or refuse all together, there is no third alternative
The partitive is indeed a hard nut to crack. It is used
to show partial object
Söin palan kakkua : I ate a slice of a cake.
to show incomplete action
Syön kakkua : I am eating cake.
En syönyt kakkua : I did not eat (any piece of) cake.
with numerical expressions when the number is other than one
Söin kolme palaa kakkua : I ate three slices of cake.
in questions to show "any"
Onko meillä kakkua? : Have we any cake?
- Onko sinulla uusi tabletti? : Have you got a new tablet?
Somehow the questioner knows or suspects that the questionee has a new tablet and asks for a confirmation (and probably wants to see it).
- Onko meillä radiota/televisiota? : Have we any radio/television?
The questioner doesn't even know, whether we, e.g. the family/household, have any radio/televion at all.
There is a flowchart which might be useful.
I come from a part of Finland where one would ask the question above using negation
- (dialect) Ei meil radio o? → (standard) Eikö meillä ole radiota? : Don't we have any radio?
The idea behind such a complex expression is, that the questioner is prepared to hear, that there is not any radio, and by that way the questionee is not put into an unpleasant situation. So it's a kind of saving the questionee's face.
Luckily Duolingo teaches the standard language, and you won't see such constructions.
You can also put 1 in partitive if you wanted to ask if someone happened to have a new tablet. Probably the reason it is not in partitive is because this kind of sentence doesn't come up very often.
"Hi, I would have a use for a new car, do you have any?" "Hei, minulla olisi käyttöä uudelle autolle, onko sinulla yhtään [uutta autoa]?"
You're right that there is a partitive form of yksi, but it's yhtä as Annika says. It is indeed rarely used as such an expression is quite emphasising.
- Kuinka kauan käytät yhtä paitaa? : How long do you use one shirt?
Note, there is also an adverb yhtä : equal(ly), as, same, which is more common.
- Konjakki on hyvää, mutta mallasviski on yhtä hyvää : Brandy is good but malt whisky is equally good.
See Wiktionary for more examples.
Yhtään is an adverb meaning "at all".
- Etkö pidä yhtään omenista? : Don't you like apples at all?