isn't this a double negative sentence if nada means "nothing". So he does not buy you nothing?
It is not bad Spanish grammar to use two negative in order to add emphasis. The question could equally be translated as "He buys you nothing?" What is important to remember is that "anything" can be substituted for "nothing" in a translation like this, which must of necessity be colloquial and thus doesn't have exactly the same syntax.
The end of the sentences are being cut off at the last syllable. It varies from question to question but seems worse with the male speaker. I started noticing this change yesterday.
I've had the the same problem with the male speaker since he was introduced. I often have to play his recording several time to, finally, arrive at the end of the sentence. It's interesting, though to try to guess where he's going.
I translated this to be "he isn't buying you anything". Is that not the same thing?
"He is not buying you anything" was accepted 8/6/2018. You should report this.
Colloguially, we say "He doesn't buy you nothing." Shouldn't that be accepted?
Hmmm. I have heard things like "He don't buy you nothin'" only as a joke. Double negatives are generally considered bad form, and I wouldn't want to encourage an English learner to use this construction.
yes, it's considered bad form because it's somewhat ambiguous. To some people a double negative makes it really negative and others a double negative makes a positive.
I wondered if "He don't buy you nothing" wouldn't be reasonable, but I grew up in the southern U.S. where that phrasing is more normal. I suppose it's not really considered "proper" English, although how much that matters depends upon how much of a purist you are.
Fortunately, most of us aren't purists but we should at least aim for "standard" English --- and presumably standard Spanish. "He don't buy you nothing" is pretty far from standard.
BTW, I got curious this morning about which languages support double negation and which don't. Wikipedia has a fascinating extended article about this, for anyone interested:
"Languages where multiple negatives affirm each other are said to have negative concord or emphatic negation. Portuguese, Persian, Russian, Spanish, Neapolitan, Italian, Japanese, Bulgarian, Czech, Polish, Afrikaans, Hebrew, Ukrainian, and some dialects of English, such as African-American Vernacular English, are examples of negative-concord languages, while Latin and German do not have negative concord. It is cross-linguistically observed that negative-concord languages are more common than those without."