Well, in the early lessons, I suppose the objective is to help us learn which endings for adjectives go with which endings for nouns, and that seems like a pretty good thing to teach, even without stringing the words together into sentences. As we progress through the tree, we're exposed to all kinds of sentences containing all kinds of words in all kinds of word orders, and things can get pretty complicated.
One day, you may find yourself looking back at the Good Old Days of "nová Kateřina," "malý František" and "staré auto"... say, for example, when you're trying to untangle "I no longer remember which of Matěj's 4 older brothers married a girl from Slovakia who has been writing books since she was 14 and whose father has 77 large pigs, a small brown bear that runs very fast, and a wolf that almost lost an eye last year." :-) (Okay, maybe I exaggerate a little...)
PS - The explanation that Carlos provided for "nová Kateřina" was excellent!
Well, where I work something funny happened, i was just coming in to work and was trying to log in to my PC, It said I was disabled, so I was going to ask my manager when I heard "Did you know that Carlos has been fired?".. I was freaking out. Until my manager told me "Not you, the New Carlos, the one that was on a trial period", so see? This CAN be used, maybe not so often and in a funny way, but it CAN be used
So far we are learning adjectives and nouns, masculine and feminine. So they are pairing different adjectives with different nouns, so that we can learn how it works, such as nova instead of novy with Katerina, since it is a female name. It is just for practice :)
the duolingo's pronunciation is so bad, especially the accents... sounds like Kate'řina with quite a strong emphasis on "ři". The main accent should be on "Ka".
Olda, You're right. Pronunciation is incorrect. Emphasis must always be at the beginning of the word. Only in a small part of Moravia near the border with Poland is the accent adapted to Polish.