5. Causes of Language Evolution.

The moving factors in language history have given rise to various explanations and theories. Beginning with the 19^th century philologists of different trends interpreted the history of the Indo-European languages differently. The Indo-European Parent language was the language of full forms and full endings. So some of the philologists in the early 19^th century thought of the contemporary forms of languages and their history as being declined and degradating, for most of the Indo-European languages were loosing their richness and grammatical forms. Linguists of the natural trend supposed language to be as a living organism. They associated stages in language history with stages of life: birth, youth, maturity, old age and death. In the later 19^th century, there appeared the psychological theories of language. Linguistic changes were attributed to individual psychology and to accidental individual fluctuations. The Young Grammarians studied factual history. They concluded that there are no superior or inferior stages in language history. All languages are equal. Phonetic laws bring about changes. These laws admit of no exception. Sociolinguists believed that linguistic changes are caused by social conditions and events in external history. Some modern authors consider that causality lies outside the scope of linguistics. Linguistics should be concerned only with the facts and mechanism of the change. Others believe that linguistics should investigate only the inner causes and conditions of language evolution. External factors are of no concern of linguistic history. In accordance with this view, the main internal cause of linguistic change is the pressure of the language system. In recent decades, we observe a revival of interest in extra linguistic aspects of language history. In this connection, we may mention the Prague School and their theory of language as a functional system. The development of language came to be seen as the evolution of the language system as such. In present-day theories, great importance is attached to the variability of speech in social groups. It is given the prime importance in linguistic change. The evolution of language is one of the movements in nature and society. So it is caused by the struggle of opposites. The moving power of the development of language is made up of two main forces:

• the growing and changing needs of man in the speech community,

• the resisting force that curbs the changes and preserves the language in a state fit for communication.

These two forces manifest the two principal functions of language: expressive and communicative. The struggle of two main forces can be described as opposition. It is the opposition of thought and means of expression and the available resources of language. These general forces operate in all languages at all times. They are universal. Therefore, as for concrete facts in the history of a particular language they fail to account.