Well, the two languages use different constructions all the time. My point is that the concept is more naturally translated as "The Spanish flag" and that requiring answers which are not natural English is counterintuitive. Is there a difference in meaning or usage between 'Spaniens flagga' and 'den spanska flaggan'?
Sure they do, but when the same construction is idiomatic in both languages, we tend to not like rewrites, as they detract from the purpose of learning Swedish.
I actually disagree with you - for instance, Google offers 353 000 hits for "the flag of Spain", and Wikipedia's article on it is called "Flag of Spain".
Potentially, I guess "the Spanish flag" could have a broader meaning in specific contexts, but that's kind of ridiculous, I think, so it adds nothing to my argument. :)
Yeah personally I have no problem with "Spain's flag is..." OR "The Spanish flag..."
In fact, I think about flags a lot and I know what a lot of the world ones are, and when I went through in my head, I realised I had different constructions for some countries! e.g. It would definitely be (for me) "Sweden's is blue with a yellow cross." - or "New Zealand's flag is almost the same as Australia's." but then it would be "The Australian flag." I don't really know why.
Late answer, but that broader meaning aspect is why 'Flag of Spain' is more common. 'Spanish' is the name of the language, the name of the nationality, and the adjectival form of the name of the country. However, the language is not unique to Spain (at least, as long as you don't consider American Spanish as a separate language), so 'The Spanish Flag' could be talking about a flag associated with the language (which is not as strange as it sounds, notice how all the languages on Duolingo have a flag icon associated with them).
That differentiation in meaning is technically possible for any construct like 'The Spanish Flag' for any country that has a name linked with a language like this, but it's unusual in most other cases because Spanish is one of the few languages that's sufficiently widespread that people may associate 'Spanish' with the language before they associate it with the nationality or the name of the country.
Yeah me too. I suppose you could argue that 'yellow and red' is 'more correct' because it has more yellow than red, but yes I think in English we've developed idioms of certain colours first when we say two or three colours, no matter the context. It's probably to do with 1 syllable versus 2 syllables. For example, "blue and yellow, green and yellow, black and yellow..." but then try "Orange and purple..." could be "Purple and orange." Yellow is perhaps a special case because it ends in an open vowel sound, so "and" is a bit clumsy after it.