Subject-pronoun agreement is a basic and pernicious flaw in formal written English. It makes correctly expressing the thought “someone should lend me their coat” impossible: because subjects and pronouns must agree, a singular but indeterminate subject (“someone”) must match a singular pronoun—but English lacks an appropriate singular gender-neutral pronoun (“his or her” being formally correct but ugly). The writer must find awkward workarounds that frequently impede shis ability to communicate.
“Someone should lend me their coat” is a natural and ubiquitous construction in spoken English; writers shouldn’t have to contort it into “a lent coat from someone would please me” or anything else. So how can we get the former declared grammatically correct? Who is the relevant authority—or, if none exists, what would it take to remove formal writers’ hesitation to use this construction?
The best idea I can come up with is that the US president, the UK’s prime minister, and other leaders of English-speaking countries should make a formal statement authorizing use of “they” as a singular pronoun. If this is what it’d take, I’d happily start a media campaign to make it happen. If anyone wants to join the movement, they’re most welcome.