The Missing Pronoun by Fred Newton Scott (1885)
"To the fast-coming objections that the proposed use of [singular they] is ungrammatical, inconsistent, illogical, and impracticable, it may be replied, in general, that the English language is full of absurdities and inconsistencies, and with all its faults we love it still."
"While the critics and philologists are quarreling over the relative advantages of two different modes of expression or pronunciation, the great talking public, which cannot very well suspend communication until the mooted question is decided, goes on talking after its own fashion, and finally talks that fashion into our grammars and dictionaries."
Scott was a linguist who became the president of the National Council of Teachers of English. Later headed up the Modern Language Association