Lewis Carroll was an enthusiastic and prolific letter-writer. On New Year’s Day in 1861, aged 28, he began to keep a register of the letters he sent, and the last one it records is number 98,721. The full tally, forever unknown, is probably much higher.
The Selected Letters of Lewis Carroll (Macmillan Press, 1982), edited by Morton Cohen, has some items of interest on the subject of language use. For example: Writing to Edith Rix on 15 January 1886, Carroll teases her about a spelling error and about her choice of preposition after different: she uses to, but he favours – insists on – from:
Now I come to your letter dated December 22nd, and must scold you for saying that my solution of the problem was “quite different to all common ways of doing it”: if you think that’s good English, well and good; but I must beg to differ to you, and to hope you will never write me a sentence similar from this again. However, “worse remains behind”; and if you deliberately intend in future, when writing to me about one of England’s greatest poets, to call him “Shelly”, then all I can say is, that you and I will have to quarrel! Be warned in time.