The main directions in linguistics and modern methods of 19th and 20th centuries

The 19th-century development of the comparative method It is generally agreed that the most outstanding achievement of linguistic scholarship in the 19th century was the development of the comparative method, which comprised a set of principles whereby languages could be systematically compared with respect to their sound systems, grammatical structure, and vocabulary and shown to be “genealogically” related. As French, Italian, Portuguese, Romanian, Spanish, and the other Romance languages had evolved from Latin, so Latin, Greek, and Sanskrit as well as the Celtic, Germanic, and Slavic languages and many other languages of Europe and Asia had evolved from some earlier language, to which the name Indo-European or Proto-Indo-European is now customarily applied.