It is, however, the vocabulary of the language that has undergone the greatest modifications, as is indeed the case in all literary dialects; for it is beyond the power of grammarians to control change in this direction. Thus we find that the vocabulary has been greatly extended by derivation and composition according to recognised types. At the same time there are numerous words which, though old, seem to be new only because they happen by accident not to occur in the Vedic literature. Many really new words have, however, come in through continual borrowings from a lower stratum of language, while already existing words have undergone great changes of meaning. This later phase of the ancient language of India was stereotyped by the great grammarian Panini towards the end of the fourth century B.C. It came to be called Sanskrit, the "refined" or "elaborate" (sam-skri-ta, literally "put together"), a term not found in the older grammarians, but occurring in the earliest epic, the Ramayana. The name is meant to be opposed to that of the popular dialects called Prakrita, and is so opposed, for instance, in the Kavyadarça, or Mirror of Poetry, a work of the sixth century A.D. The older grammarians themselves, from Yaska (fifth century B.C.) onwards, speak of this classical dialect as Bhasha, "the speech," in distinction from Vedic. The remarks they make about it point to a spoken language. Thus one of them, Patanjali, refers to it as used "in the world," and designates the words of his Sanskrit as "current in the world." Panini himself gives many rules which have no significance except in connection with living speech; as when he describes the accent or the lengthening of vowels in calling from a distance, in salutation, or in question and answer. Again, Sanskrit cannot have been a mere literary and school language, because there are early traces of its having had dialectic variations. Thus Yaska and Panini mention the peculiarities of the "Easterns" and "Northerners," Katyayana refers to local divergences, and Patanjali specifies words occurring in single districts only. There is, indeed, no doubt that in the second century B.C. Sanskrit was actually spoken in the whole country called by Sanskrit writers Aryavarta, or "Land of the Aryans," which lies between the Himalaya and the Vindhya range. But who spoke it there? Brahmans certainly did; for Patanjali speaks of them as the "instructed" (çishta), the employers of correct speech. Its use, however, extended beyond the Brahmans; for we read in Patanjali about a head-groom disputing with a grammarian as to the etymology of the Sanskrit word for "charioteer" (suta). This agrees with the distribution of the dialects in the Indian drama, a distribution doubtless based on a tradition much older than the plays themselves. Here the king and those of superior rank speak Sanskrit, while the various forms of the popular dialect are assigned to women and to men of the people.