There are a few details in Croatian which don’t really fit into the overall scheme of things.
First, there’s a phrase which can be used to express color. It uses a color adjective before the noun boja color, but both are the genitive case (singular):
Majica je crvene boje. lit. The T-shirt is ‘of red color’.
Hlače su plave boje. lit. The trousers are ‘of blue color’.
Such expressions are old-fashioned and mostly obsolete. However, they are used in questions, i.e. when you ask what color is something. The answer would be just a color adjective, but in genitive singular (feminine, after boja color):
Koje boje je majica? What color is the T-shirt?
— Crvene. (G fem.) Red.
— Crvena. (N fem.) Red.
Koje boje je auto? What color is the car?
— Crne. (G fem.) Black.
— Crni. (N masc.) Black.
Alternatively, you can answer with an adjective in nominative, matching gender of the thing the question is about, as in the examples above.
This reminds of English expressions like men of honor, book of great importance, and so on. In fact, you will occasionally see more or less the same expressions in Croatian, using od¨ + G:
Knjiga je od velike važnosti. The book is of great importance.
Then, there are expressions – often overlooked in grammars and textbooks – when two nouns are used together, e.g. king George or Hotel California. The last noun is a proper noun, i.e. a name (e.g. California), and a common noun before it describes its title (e.g. king) or kind (e.g. hotel).
Croatian uses such expressions more often than English, e.g. in names of rivers, lakes, cities and countries:
ijeka Sava the Sava river (lit. ‘river Sava’)
jezero Jarun the Jarun lake (lit. ‘lake Jarun’)
Grad Zagreb the City of Zagreb (lit. ‘City Zagreb’)
Republika Hrvatska the Republic of Croatia
Now, in some of these expressions, both nouns change case, and in others, the last word (the name) is ‘frozen’ in N.
If nouns stand for a person (or an animal, as Croatian almost always treats humans as a kind of animal), both nouns always change (examples show the accusative case):
moj prijatelj Igor my friend Igor → mog prijatelja Igora
teta Ana aunt Ana → tetu Anu
This also applies to the following nouns:
For example (u¨ + DL):
ijeka the City of Rijeka → u gradu R ijeci
grad Split the City of Split → u gradu Splitu
ijeka Drava the Drava river → u rijeci Dravi
Since a great majority of rivers have feminine names in Croatian, use of r
ijeka river with masculine names of rivers is avoided. (Croatian so strongly prefers feminine river names, that even names like the Thames and the Rhine are adapted as feminine Temza and Rajna). You will mostly see ‘frozen’ masc. names of rivers, e.g. u r ijeci Dunav:
ijeka Dunav the Danube river → (?) u r ijeci Dunavu
After most other nouns, only feminine names can change, but it’s optional – names are usually not changed. Often used nouns are:
For example (again u¨ + DL):
hotel Panorama → u hotelu Panorama / Panorami
kazalište Komedija → u kazalištu Komedija / Komediji
You will see changed feminine names now and then. However, masculine names are always ‘frozen’:
hotel Westin → u hotelu Westin
jezero Jarun → u jezeru Jarun
kazalište Jazavac → u kazalištu Jazavac
Bear in mind that ‘freezing’ happens only of a general noun is before the name, if the name is on it’s own, it of course always change, e.g. u Westinu, u Jarunu, etc.
Occasionally, you’ll see a kind of reversal of the structure described above, where a proper noun (i.e. a name) describes a common noun; an example is this tube of mayonnaise:
Such combinations appear as a kind of indeclinable adjective + a noun, in writing and in speech (an example from the internet, promoting the product), where the word majoneza mayonnaise is in A, but the name preceding it is not:
Do you like Zvijezda mayonnaise?
(the rest is coming soon)