The compounding of errors.
He told me that every edition of a classic work is different. The first transcription contains errors and these are repeated, and new errors included, with each new edition that is made so that gradually the American versions, say, become less and less like the English versions.
We started to think of similes - like the way language itself evolves, he said, or perhaps the mistakes in the replication of DNA in cells until a new species forms. However, in the case of a book, of course, it is possible to go back to the original manuscript and start again (which is what he was doing).
Tonight I think about something I have often thought about - how interesting it would be to go back to listen to that first pure language of man. I suspect I would hear a grunt beginning with 'muh' and a child reaching out to be fed. The word for 'Mother' must be a universal uttering of life.