"I want a calendar."
Translation:Teastaíonn féilire uaim.
Thanks and yes apologies I meant "bia madra". Sry then I don't understand. My thinking was "bia madra" with "madra" in the nominative and NOT in the genetive to show the difference between "dog food" and "dog's food". I seem to then completely have misunderstood the exercises. Is it then correct to say that in Irish you can't really say "dog food" or "cat calendar", but would always say "dog's food" or "cat's calendar" at least in a literal sense?
No. You also can't choose whether to put the 2nd noun in a phrase in the nominative or genitive - especially for 4th declension nouns (like madra) where the nominative and the genitive are the same. As a general rule, the 2nd noun is in the genitive.
The Genitive isn't simply about possession (adding 's to the word in English). feilire cait is not "literally" "a cat's calendar" - it's "a calendar" with a genitive attribute cait - the best interpretation of that attribute will depend on context
What is the difference in English between "a book's cover" and "the cover of a book"? How about "a book cover"?
I saw that picture on "the cover of a book"/"a book's cover"/"a book cover".
Chonaic mé an pictiúr sin ar chlúdach leabhair
Note the difference between "a book's cover" and "a book cover". In the first, "book" is clearly a noun, in the second, "book" is being used as though it was an adjective, it's just an attribute of "cover", like "red" or "big" or "torn". One of the functions of the tuiseal ginideach is to allow a noun to be used as an attribute, as though it was an adjective - "a cat calendar" - féilire cait, as "cat" is being used as an attribute, so you use the genitive cait.
A complication with bia madra (other than the fact you can't tell whether madra is nominative or genitive) is that the An Coiste Téarmaíochta has decided that bia madraí (food of dogs) is more appropriate than bia madra (food of a dog) since that exercise was created. There used to be a mix of singular and plural nouns used, but now terms like "cat food", "baby food", "bird food", "rabbit food" all use the genitive plural - bia cat, bia leanaí, bia naíonán, bia éan, bia coiníní - whereas phrases like "breakfast food" use the genitive singular bia bricfeasta.