In English one would not "eat a soup" even if mananca o supa is good Romanian.
What do you mean? There are plenty of people who would use "eat" with soup.
I am referring to using the phrase "eat a soup"; including the indefinite article is possible in English but sounds strange.
"Eat a bowl of soup" or just "eat soup" is what I would say.
The only way this woud be possible is if "soup and a salad" was a menu option, and they were "eating a 'soup and a salad'", but even then it sounds awkward.
So, to say: "The boy eats soup and salad", just omit the "o"s, correct?
No "a salad" is fine in English its just the "a soup" that doesn't sound right. "A bowl of soup" or just "eat soup" is more accurate.