There is no subject so deeply interesting and important to rational beings as the knowledge of language, or one which presents a more direct and powerful claim upon all classes in the community; for there is no other so closely interwoven with all the affairs of human life, social, moral, political and religious. It forms a basis on which depends a vast portion of the happiness of mankind, and deserves the first attention of every philanthropist. Great difficulty has been experienced in the common method of explaining language, and grammar has long been considered a dry, uninteresting, and tedious study, by nearly all the teachers and scholars in the land. But it is to be presumed that the fault in this case, if there is any, is to be sought for in the manner of teaching, rather than in the science itself; for it would be unreasonable to suppose that a subject which occupies the earliest attention of the parent, which is acquired at great expense of money, time, and thought, and is employed from the cradle to the grave, in all our waking hours, can possibly be dull or unimportant, if rightly explained. Children have been required to learn verbal forms and changes, to look at the mere signs of ideas, instead of the things represented by them. The consequence has been that the whole subject has become uninteresting to all who do not possess a retentive verbal memory. The philosophy of language, the sublime principles on which it depends for its existence and use, have not been sufficiently regarded to render it delightful and profitable. The humble attempt here made is designed to open the way for an exposition of language on truly philosophical principles, which, when correctly explained, are abundantly simple and extensively useful. With what success this point has been labored the reader will determine. The author claims not the honor of entire originality. The principles here advanced have been advocated, believed, and successfully practised. William S. Cardell, Esq., a bright star in the firmament of American literature, reduced these principles to a system, which was taught with triumphant success by Daniel H. Barnes, formerly of the New-York High School, one of the most distinguished teachers who ever officiated in that high and responsible capacity in our country.