You have with you three or four of the best English authors, Dryden, Atterbury, and Swift; read them with the utmost care, and with a particular view to their language, and they may possibly correct that curious infelicity of diction, which you acquired at Westminster.  Mr. Harte excepted, I will admit that you have met with very few English abroad, who could improve your style; and with many, I dare say, who speak as ill as yourself, and, it may be, worse; you must, therefore, take the more pains, and consult your authors and Mr. Harte the more.  I need not tell you how attentive the Romans and Greeks, particularly the Athenians, were to this object.  It is also a study among the Italians and the French; witness their respective academies and dictionaries for improving and fixing their languages.  To our shame be it spoken, it is less attended to here than in any polite country; but that is no reason why you should not attend to it; on the contrary, it will distinguish you the more.  Cicero says, very truly, that it is glorious to excel other men in that very article, in which men excel brutes; speech.

Constant experience has shown me, that great purity and elegance of style, with a graceful elocution, cover a multitude of faults, in either a speaker or a writer.  For my own part, I confess (and I believe most people are of my mind) that if a speaker should ungracefully mutter or stammer out to me the sense of an angel, deformed by barbarism and solecisms, or larded with vulgarisms, he should never speak to me a second time, if I could help it.  Gain the heart, or you gain nothing; the eyes and the ears are the only roads to the heart.  Merit and knowledge will not gain hearts, though they will secure them when gained.  Pray, have that truth ever in your mind.  Engage the eyes by your address, air, and motions; soothe the ears by the elegance and harmony of your diction; the heart will certainly follow; and the whole man, or woman, will as certainly follow the heart.  I must repeat it to you, over and over again, that with all the knowledge which you may have at present, or hereafter acquire, and with all merit that ever man had, if you have not a graceful address, liberal and engaging manners, a prepossessing air, and a good degree of eloquence in speaking and writing; you will be nobody; but will have the daily mortification of seeing people, with not one-tenth part of your merit or knowledge, get the start of you, and disgrace you, both in company and in business.

You have read “Quintilian,” the best book in the world to form an orator; pray read ‘Cicero de Oratore’, the best book in the world to finish one.  Translate and retranslate from and to Latin, Greek, and English; make yourself a pure and elegant English style:  it requires nothing but application.  I do not find that God has made you a poet; and I am very glad that he has not:  therefore, for God’s sake, make yourself an orator, which you may do.  Though I still call you boy, I consider you no longer as such; and when I reflect upon the prodigious quantity of manure that has been laid upon you, I expect that you should produce more at eighteen, than uncultivated soils do at eight-and-twenty.