"What are the girls eating?"
Translation:Что едят девочки?
They are both possible. It is hard to say which is better because the sentence is so short. With pronouns "Что ты ешь?", "Что они едят?", "Что мы едим?" would definitely be more common if you do not wish to put a special emphasis on the subject. As for "girls", both work. If you were interested what girls (or the girls), of all other people present, are eating, you would use the sentence in the header. If you were just interested in what they are eating (regardless of what other people eat), "Что девочки едят?" would work rather well.
When I hear/read Что едят девочки (What are the girls eating), for some reason I think it means "What is eating the girls". Is that a common misconception? Is that an interchangeable meaning of the sentence? It happens often in English, where for example, reed and read are two different things that sound exactly the same in speech. Is this something where you would need more context to understand the difference?
This is where the noun cases are important, since Russian word order is not as important as English word order.
Что едят девочки? What do girls eat?
Что ест девочек? What eats girls?
In the first sentence, the subject is always in the nominative case, so the noun девочки is in the nominative. In the second sentence, the subject is что, and what it eats is in the accusative case, so the noun девочек is in the accusative.
Also "девочки" is plural, so the verb "есть" is conjugated to third-person plural "едят." "Что" is singular, so the verb "есть" is conjugated to the third-person singular "ест." So the construction of the sentence is completely different based on the subject and the direct object.
Not exactly. Almost all nouns in English require articles, with numerous exceptions. "What are girls eating," sounds incorrect in English. The present continuous tense implies the current moment which implies specific "the girls are eating." The simple present tense works without an article, though. "What do girls eat?" In Russian there are no articles, so you don't need эти unless you're specifying "these/those girls."
Aye! Moreover, Kiev is also southern. Travelling around Russia I noticed that кушают said in that regions very often, a much less in central Russia and very rare on east (where кушают in colloquial talks I heard only from Jewish). But every russian will understood you quite well.
That is odd. Есть (поесть, съесть) are quite a bit more common than кушать (покушать, скушать) though the latter are by no means rare. At least, they are common when talking about real meals you have or inviting someone you know to have lunch with you. I do find кушать funny in generic or non-human contexts like "I do not eat meat" or "These animals eat insects" (but you can sometimes encounter such use).
Also, linguists are fond of кушать—for obvious reasons.