The distinction between country culture and language needs to established well because certain countries do not have a singular or United culture, just look at the random splits the europeans like the sykes-picot
That's the point of the ideas project concept. You may have adopted a culture as a national identity but it does not mean that there are not many cultures within that nation. A culture is not a language. Many cultures speak English and Spanish, for example. The language may bind those cultures into a group that tends to favor one another. But they don't define the culture. A national identity is a culture but there is no prerequisite that a culture have a nation to define it.
The US shows a good example. You have different cultures here, Irish, Spanish, Norwegian, German, Russian, French, English, Scottish, many tribes of the Native Americans hanging on to some cultural identity, some home grown ones, Confederate, Californian, Texan, Yooper, and yet while you can see how strong some of these are in different regions across the country, USUALLY, the strongest identifying culture is simply United States. Perhaps that came about over time as nearly as soon as that cultural concept emerged it was adopted as a National identity (civic) by the rebel nation that split from the English, who had long ago adopted English as their national identity. In many ways it was largely French and a strong influence from the Native American cultures that weakened the cultural tie to English on these shores, a big part of why it's tough to make colonies in the middle of distant foreign-developed lands a difficult prospect.
Then we had the rise of the Confederates and at a point they had grown so strong that they attempted to secede from the nation as well under a new national identity of that culture.
We have not seen Creole attempt to break away, but Texas and California have at times shown strength enough to consider it.