Translation:Những cái ca
I understand that những and các are interchangeable, but are there any instances when one is more 'appropriate' than the other?
In Vietnamese grammar, các is used for definite objects, also indicates "each". những on the other hand is used for indefinite objects. By familiarize with more Vietnamese sentences, you will be able to understand more the use of các and những,
I thought ca was a pitcher, I've never seen a mug (beer glass?) referred to as anything but a Ly?
The specific English grammatical terms are useful - My educated guess is that one way "những" can be used is for plural nouns with adjectives describing it (Những con gà lơn) while one way "các" is used is for "base" nouns with nothing following it in that sentence (Các con gà ăn cơm). How does that relate to the "indefinite and definite object" usage? I am grateful for your familiar understanding of Tiếng Việt!
Because the Duolingo VN team made it that way. :D I agree with you that "cốc" is one of the possible translations of "mug".