"madra" is of the fourth declension
confirmed by the dictionary, which also shows its male...
rules for fourth declension are here
so, "madra" nom. sing. has modified to "madra" gen. sing.
No other rules apply because no articles nor possessives are present
Why is bia mhadra not acceptable? Can that not mean "a dog's food"?
Would the second noun be lenited, if it were a feminine noun? Maybe that is what I was thinking...
unlenited after masculine nouns in the nominative singular
e.g. fear céile = husband
lenited after masculine nouns in the weak plural (on slender consonants)
e.g. na fir chéile = the husbands
lenited after masculine nouns, that are in the genitive themselves (on slender consonants)
e.g. an fhir chéile = of the husband, teach pobail bhaile = the church of a town
lenited after feminine nouns in the nominative singular
e.g. bean chéile = wife
How would one differentiate between "dod food" and "a dog's food" in Irish?
One of the options in the selection list was "
*madraí*" (ie "bia madraí"). Duolingo rejected this. NEID, however, gives "bia madraí" as the translation of "dog food"
Some other examples found:
bia madraíagus beatha éan
bia madraíar na seilfeanna
From a story in Feasta
cuóta taraife bliantúil Comhphobail le haghaidh
bia madraínó bia cat
From the Corpas Comhthreomhar on Gaois.ie
[Note how the similar, emphasised, examples also use the genitive plural of the qualifying noun "cat" and "éan"]
Obekim didn't get a "type what you hear" exercise, he got a "Select All Correct" exercise - I'm not sure if Duolingo still presents that type of exercise any more.
As Obekim wrote his post over two years ago, it's possible that there wasn't even any audio for this exercise at that time.