Change is continually taking place in the vocabulary of English, just as with other languages. In many instances the types of changes have their roots in the developments which began several centuries ago. The following article, available in PDF form, examines several changes happening in present-day English and presents them in a structured manner. It also attempts to show these changes as continuations of processes which have been on-going in English for some considerable time.
Productive lexical processes in present-day English
Detailed discussions of lexical change in the history of English can be found in the following book:
Brinton, Laurel and Elizabeth Traugott 2005. Lexicalization and language change. Cambridge: University Press.