Antoine Meillet demonstrated in 1906 that language corresponds exactly to the definition of a social fact. “Language is… eminently a social fact.” In effect, this is explicitly implied in the definition proposed by Durkheim. A language exists independently of the individuals who speak it, and although it has no reality outside the sum of these individuals, it is nevertheless, due to its general character, exterior to each of them, thus proving that it does not depend on any single person to modify it and that every individual deviation from common usage provokes a reaction.” Meillet shows moreover that the causes for semantic changes are social in character and can be classified into three main types. They are explained by changes in the thing meant, by the transfer of words from one social group to another, and, thirdly, by intrinsic linguistic conditions. In fact the causes are outside the linguistic system itself—the causes for changes of the third type are not the linguistic conditions themselves but lie in whatever has induced these conditions—and this is true of every linguistic system (by system of a language I mean also the relationships between the words and their sense). The division of a society into classes or castes produces differences in vocabulary, grammar, phonetics and phonemics, in style, etc. The adoption of a new language by a people can lead to profound changes through the agency of the substratum. The material and spiritual evolution of a society is followed by the appearance of a great number of new words and new meanings which have repercussions on other parts of the linguistic system, a characteristic aspect of the linguistic development of Europe and of the languages of every society of our time which has become industrialized and has adopted modern Western civilization.