Another translation issue -- "sour cream for dinner" sounds like he will only be eating sour cream. English would more naturally say, "Does he like sour cream at dinner?"
No, "Does he like sour cream at dinner" will be "Він любить сметану за вечерею?"
"На вечерю" does sound totally like that's the only thing he's eating (at least to me, don't know about other Ukrainians from other regions). So yeah, it doesn't sound natural :) A little nonsensical, but well, Duo is like that sometimes
So does this sentence -- in Ukraineian -- really ask about eating only Sour Cream? I mean, if you were speaking to a friend in Ukrainian, would you think him weird to ask this question?
As for me (again, my Ukrainian can be different from the Ukrainian spoken in other parts of Ukraine), it does sound like really asking about only sour cream. I would find it weird if to the question "Що ти любиш на вечерю?" (What do you like for dinner?) somebody answered "sour cream". I would ask "Sour cream and what?" or think they're following some crazy diet.
Ha, ok - thanks for clarifying. I live in L'viv, but I also know that different regions have somewhat different dialects. I also know that I haven't learned nearly enough Ukrainian for someone who lives here :D