I think some of his methods and principles could apply to other subjects besides Latin.
Two years of this simple conversational Latin of the kind that can be picked out or made up from Terence, Cicero's letters, Aulus Gellius and Augustine, practice in writing easy sentences in the simpler constructions of the sermo cotidianus of Rome, avoiding meanwhile the periodic sentence and finished works of adult literature (not made for young Roman boys) and keeping to thoughts and expressions within the sphere of boyhood, using coins, graffiti, inscriptions on cups, sling stones, weapons and other things of common life, saying maxims, proverbs, and other immortal quotable phrases (dulce et decorum est pro patria mori), trying the fables, "tales and golden histories" so far as we can, perhaps opening a little mythology in Ovid, reading aloud in selected parts of the Psalter and the Gospels, and writing, writing, writing the Latin he says, perhaps making some for himself in the form of a letter or story -- something like this is the course that will bring a boy ready, really ready, and happy to beging his harder task of reading the serious literary Latin, equipped with a vocabulary that is sounding in his ears, a natural habit of saying and writing simpler Latin and a large store of satisfying information. Does it sound too easy? It is hard enough for a boy of twelve.
Where does grammar come in? Everywhere -- at first most simply by sorting words according to their kinds and then by moving on, one step at a time, to arrange them clearly under the laws of the language. When the dreaded "exceptions" occur, help the boy to use his wits and, if need be, his wit to fasten them in his mind. Take a most simple example. Words that look feminine and are masculine may annoy him awhile. Let his humor help him in handling agricola and pirata by saying in Latin, "The bad farmer loves the good pirate." He will never forget this. Thus the boy is continually finding the grammar inside the used and usable language, instead of trying first to find the language in the grammar. He begins to learn the rules of the game by watching and trying the game. He may next go on to understand the game better by mastering the rules. This done, he knows how to play the game. How well he will play it then depends mainly on himself.
Where does the literature come in? Everywhere -- just as soon as he begins to read the easier Latin books, boys' reading at first, men's reading as soon therafter as is practicable. Then as vistas begin to open and perspectives to length, he begins to get his reward. He has climbed the Hill Difficulty and may look out with clear vision upon the broad real of literature and the long perspectives of history.
A life given to teaching Latin has gradually forced me to conclude that this is the true way to bring Latin alive into our modern consciousness. It does not call for skilled conversationalists as teachers. Three months oral practice will give almost any Latin teacher enough of a start. In classical training, as elsewhere, it is the beginning that settles almost everything. This is the method and spirit which in varying forms inspired the teachers of the Renaissance. And what is true for Latin is as true for Greek. Utrique eadem via est. (Quintilian)