Ask the experts?
In Rio de Janeiro they have set up a grammar hotline, according to the BBC. (thank you, Mr. Gitomer, for the link). Residents unsure about spellings and the use of accents in Portuguese may call up for advice. Apparently, there is anxiety in Brazil about correctness in using the language, because errors in grammar are stigmatized as indicating a lack of education. (Here, they appear to be a qualification for public office.)
Mr. Gitomer invited me to consider, “So, what happens when one calls with the same question eight times (the number of experts) and one gets eight different answers.”
Yes, imagine a grammar hotline for speakers of English. A lucky caller might get Bryan Garner or Jan Freeman or Bill Walsh, all of whom I generally agree with, which indicates that they are persons of rare discernment. An unlucky caller might get Martin Estinel, the British proponent of an Academy of English, or one of those glassy-eyed devotees of The Elements of Style, or the ignoramuses who inveigh against passive constructions without knowing what the passive voice is.
Things may be different in Portuguese, though I doubt it, but in English, beyond the rules of grammar that both prescriptivists and descriptivists recognize, there is a broad muddy ground of mixed choices. Mr. Garner, for example, has in the third edition of Garner’s Modern American Usage established a five-point scale of usage, from “Rejected” to “Fully accepted,” and there is a lot going on in the continuum between those poles.
Reasonable people can disagree over points of usage, but in these discussions, as in politics, it is the unreasonable people who appear to be loudest. You need to tune in to the reasonable people.
Fortunately, you’re reading here.