The Complete English Tradesman by Daniel Defoe

In the last chapter I gave my thoughts for the instruction of young tradesmen in writing letters with orders, and answering orders, and especially about the proper style of a tradesman's letters, which I hinted should be plain and easy, free in language, and direct to the purpose intended. Give me leave to go on with the subject a little farther, as I think it is useful in another part of the tradesman's correspondence.

I might have made some apology for urging tradesmen to write a plain and easy style; let me add, that the tradesmen need not be offended at my condemning them, as it were, to a plain and homely style -- easy, plain, and familiar language is the beauty of speech in general, and is the excellency of all writing, on whatever subject, or to whatever persons they are we write or speak. The end of speech is that men might understand one another's meaning; certainly that speech, or that way of speaking, which is most easily understood, is the best way of speaking.