No one will deny the fact that such differences exist, as between Germans, Frenchmen, and Englishmen, for instance. This difference is not racial, as they all belong to the Caucasian race. It can scarcely be climatic with nations whose territory is adjacent to each other; nor is it likely to be religious, historical, or political. There is nothing very decidedly different in the situation and composition of these various nations and the individuals of which they are composed, except their _language_. I maintain that language is not only the main point of difference, but that it is the cause and origin of all other main points of difference. As language is the main gift which distinguishes men from animals, so it is also the principal distinguishing mark as between one nation and another. I maintain, and expect to prove, that the language--that is, any specific language--acquired in childhood becomes an integral part of a person's organization, as positively so as any of his other natural faculties; and that he cannot change it, that is, _in an idiomatically correct manner_, without changing, to some extent, the drift of his entire organism. As soon as I began to succeed in speaking the English language as it is spoken in this country, idiomatically correct, I changed my nature, to some extent, from that of a German to that of an American; nor is it possible to learn to speak any language idiomatically correct without undergoing a similar change. Not alone my mode of vocal expression, but my motions, my habits, nay, my very _features_, yes, even my way of _thinking_, in some respects, have been subjected to such a change; modified, of course, by heredity, previous habits, and the constant reversion of all this by the frequent recurrence to my native tongue. In using the term "idiomatically correct" I mean of course that mode of expression which is peculiar to a language, its general cast, and which is representative of its genius and spirit. To what do I attribute so powerful an influence?