A pronoun… will aptly reflect the number of its antecedent: they does not refer to one person, no matter how many personalities she or he has, or how eager you are to skirt the gender frays. – Karen Elizabeth Gordon, “Agreements,” The Deluxe Transitive Vampire: The Ultimat
Linguists are no different from any other people who spend more than nineteen hours a day pondering the complexities of grammar and its relationship to practically everything else in order to prove that language is so inordinately complicated that it is impossible in principle for people to talk. – Ronald W. Langacker (b.1942), Language and Its Structure, 1973

