The English is […] of all the languages of its kindred, the one which most remarkably illustrates that mode of linguistic change consisting in the loss of formal grammatical distinction by synthetic means; there is no other known tongue which, from having been so rich in them, has become so poor; none which has so nearly stripped its root-syllables of the apparatus of suffixes with which they were formerly clothed, and left them monosyllabic.
- Whitney (1875), a pag.105

We have rudely made one classification of [...] linguistic changes, founded on the various purpose which they subserve: namely, into such as make new expression, being produced for the designation of conceptions before undesignated; and such as merely alter the form of old expression; or, into additions and alterations. It will, however, suit our purpose better to make a more external division, one depending upon the kind of change rather than upon its object […] We may distinguish then:- I. Alterations of the old material of language; change of the words which are still retained as the substance of expression; and this of two kinds or subclasses: 1. change in uttered form; 2. change in content or signification; the two […] occurring either independently or in conjunction. II. Losses of the old material of language, disappearance of what has been in use; and this also of two kinds: 1. loss of complete words; 2. loss of grammatical forms and distinctions. II. Production of new material; additions to the old stock of a language, in the way of new words or new forms; external expansion of the resources of expression. This classification is obviously exhaustive; there can be no change in any language which will not fall under one or other of the three classes here laid down.
- Whitney (1875), a pag.44