The historical development of a language is a continuous, uninterrupted process without sudden breaks or rapid transformations. Therefore any periodisation imposed on language history by linguists, with precise dates, might appear artificial. There are some periodizations of the history of English language. The author of the first scientific historical phonetic and grammar of En. Language. H. Sweet suggested the periodization that corresponds to the morphological structure of different centures. He called the Old English Period – ‘The period of full endings ‘, the M. E. P. – ‘The period of reduced endings’ , the New En. P. – ‘The period of lost endings.’