"The boy and I speak Romanian."
Translation:Eu și băiatul vorbim limba română.
I think that, while in English it may be preferred to say the boy and I instead of the other way around, it is easier for someone learning to say eu și băiatul in Romanian as the reversed order would be băiatul și cu mine which would be harder to understand, like why is it cu mine instead of eu.
"Băiatul şi cu mine" is the correct word-for-word translation as someone else pointed out above. "Eu şi băiatul" is the easier construction, hence the inversion.
Here's why (the reason is a bit technical so bear with me):
"Eu şi băiatul" --> multiple subject (subiect multiplu). Both words are in the nominative, which is the most common case for the subject in Romanian. The first word "eu" is a personal pronoun therefore we use it as is. The second word "băiatul" is a noun. Generally, nouns in the subject position (Nominative) require either a definite or an indefinite article. Here we have the definite article ("-l" for most maculine and neuter nouns, with the vowel "u" before it, to connect more easily two consonants). If we had two nouns here, both would be articulated:
"Fata şi băiatul vorbesc limba română." = The girl and the boy speak Romanian.
You can change the position of the two nouns and the rest of the sentence remains the same: "Băiatul şi fata vorbesc limba română." Why? Precisely because they are two nouns. Both require and accept their respective definite articles.
However, the Duolingo sentence does not give us two nouns in the subject position. It gives us a personal pronoun "eu" and a noun "băiatul."
If we use "eu" first, as in "eu şi băiatul," the sentence is grammatically correct and both words are in the nominative.
If we use "băiatul" first we get in trouble with the pronoun. [By the way, this is also the case with English when you use a multiple subject where one of the terms of the subject is a pronoun. In English you can say: "They boy and I" but not "I and the boy."
In Romanian, it is the opposite. You can say "Eu şi băiatul," but not "Băiatul şi eu."]
So, why do we get in trouble in Romanian? Because of the definite article -l required by the noun. If "băiatul" is first, the article -l requires that any other word used in a relationship of equality with the noun be articulated. The conjunction "şi" is used in relationships of grammatical equality. However, we cannot articulate a personal pronoun. What we can do is change it from Nominative to Accusative and add the preposition "cu" (the Accusative is often introduced by "pe" or "cu").
Hence, "Băiatul şi cu mine." --> "(cu) mine" is the accusative form of the personal pronoun "eu"
If we had two personal pronouns in the subject position, we could inverse them without any changes.
El şi ea vorbesc româneşte.
Ea şi el vorbesc româneşte.
Duolingo chose the most complicated scenario where we have a personal pronoun and a noun in the subject position without explaining the difficulty we run into with inversions. This is pedagogically problematic.
I hope this helps.
Cu mine means "with me". Similar constructions exist in Slavic languages (instrumentative case doubles as comitative case) and Latin (enclitic -que in Senatus Populosque) and also other romance langauges (ie. Spanish "conmigo" "with me"). The Romanian "cu" seems to have evolved from latin "cum" "with".
"Română" means "Romanian."
"Româna" = "the Romanian" as in "the Romanian language" (language is implied). You can also say "limba Română" where "limba" ("language") is stated.
So, the difference between "română" and "româna" is that "româna" has the definite article -a received by feminine nouns (româna is feminine), whereas "română" doesn't have an article.
I found an answer on wordreference.com, hope it helps. "They both mean Romanian, but they are used in different context. "Română" is usually used for the language. "Limba română" means "the Romanian language". "Românesc" is something that has to do with Romania. For example "produs românesc" means a something that is produced in Romania." https://forum.wordreference.com/threads/basic-question-2-rom%C3%A2n%C4%83-vs-rom%C3%A2nesc.3191303/