I agree with Claudia581500. "Do you want to eat a vegetarian pizza" is not only correct, but more consistent with the 'Correct' answers that Duolingo insists on for other sentences in this lesson. I've reported it.
It is correct, report it!
Edit: I scrolled down and see that it has been corrected.
This item had no audio nor did it allow me to select the can't listen now option. Using Chrome on iPad.
I just got the notification that they have corrected this exercise, and now accept Claudia's alternative. One of the things that I love about the Esperanto Duolingo team is that they are very responsive and appropriately flexible.
'Do you want to eat vegetarian pizza?' is wrong. The indefinite article 'a' should precede the word 'pizza'.
I disagree, RolandasNa2. There are two valid and normal sentences in English. 1) 'Do you want to eat vegetarian pizza?' 2) 'Do you want to eat a vegetarian pizza?' They have slightly different meanings. I probably wouldn't say 'a vegetarian pizza' to a group of twenty friends, nor to one friend, if we wanted a quick slice of pizza, before playing tennis.
Both English sentences are translated the same into Esperanto, since it doesn't have an indefinite article. Translating from Esperanto to English, both answers are equally correct, unless more context is available to clarify a choice.
I'm guessing that you aren't a vegetarian. I am, and I ask about 'vegetarian pizza' every time I order a pizza. I did a Google search on 'vegetarian pizza', and it reported 461,000,000 hits. If one of each million of those are native English speakers, then there are at least 462 of us who use the expression.
I am a vegetarian actually, and 462 is not a lot of people, relatively speaking. There are vegetarian options, like cheese pizza and vegetable (veggie) pizza, but no one orders a "vegetarian pizza." I'll reiterate that I did say there is technically nothing wrong with the phrase, just that, in my experience, it is an uncommon way to refer to a pizza.
Well, we still have the remaining 460+ million sites to check. But here is a quote from the first site that Google offered me. "Who says meat lovers get to have all the fun? From spinach-artichoke to salsa-stuffed to Mediterranean-style, these vegetarian pizza recipes prove fresh produce tastes even better by the slice. https://www.tasteofhome.com/collection/pizzas-veggie-lovers/view-all/
Your statement that "no one orders a 'vegetarian pizza' is disproved by a single example. In a restaurant, people are most likely to order items that are written on the menu. If there is only one vegetarian option, then I might use the words, "I want the vegetarian pizza." More frequently, when I call up a restaurant, and I don't know the menu, I will ask, "Do you have a vegetarian pizza".
Here's a quote from the second web site that Google offered me: "here's 18 vegetarian pizza ideas to get you going." https://www.thespruceeats.com/creative-vegetarian-pizza-recipes-3378587
Here's a quote from the third website in the Google search. "Looking for vegetarian pizza recipes?"
Three out of three, so far...
Google search is not an authoritative source for anything. I actually googled "vegetarian pizza" myself before posting my first comment; all the websites more or less describe veggie pizzas, and I in my experience most people would just say "veggie pizza" not "vegetarian pizza." In fact, the websites I checked seemed to use "veggie" and "vegetarian" interchangeably at times. Furthermore, I'm actually fine with their use of "vegetarian pizza" in that context, because they are listing and describing various vegetarian recipes. Again, I never said the phrase was incorrect, but I disagreed with its use in the context of the sentence.
I also find it strange that you would ask a restaurant if it serves a vegetarian pizza; I don't know of many restaurants that serve pizza but don't offer a cheese or veggie option. The same goes for your example of a restaurant only offering one vegetarian option, although I am sure there are restaurants that do.
Again, I don't think the phrase is wrong, and I am sure there are plenty of people that use it in the way you've descried. My original point is that I don't think most people would ask someone "Do you want a vegetarian pizza?" because the answer wouldn't help you place an order, because then you need to ask which vegetarian option the person wants: cheese, veggie, Mediterranean, etc. Again, I'm sure there are people like who do this, but in my experience with my dialect/variety of English, it just sounds off. I'll finish by saying that the more I say it, the less weird it sounds, and I could hear myself saying it in some situations. Again, I've never said that it is wrong, because it is certainly not, but in context it sounds weird to me.
A lot of passion in this thread. FWIW, I'm a native American English speaker (as is Nekoninda). "Vegetarian pizza" sounds totally normal to me. A veggie pizza might not be vegetarian if it uses animal products in the crust, for example.
My original point is that I don't think most people would ask someone "Do you want a vegetarian pizza?"
I am inclined to agree with you - but I will say that I routinely speak Esperanto in a vegan cafe on pizza night, and I very often say that I DON'T want to eat vegan pizza. In the right context, the original sentence is totally natural.