[…] the prevailing direction of phonetic change is from the extremities toward the middle of the alphabetic scheme: the mutes become fricatives; the ‘a (far)’ is changed to ‘e (they)’ and ‘i (pique)’, or to ‘o (note)’ and ‘u (rule)’. Movement in the contrary direction is by no means unknown; but it is exceptional or under special causes: it is […] the eddy in the current.
- Whitney (1875), Pag. 69-70

If there were penalties following slips in utterance, the subject of phonetic change would make but a small figure in our comparative grammars.
- Whitney (1875), Pag. 148

Phonetic changes are especially likely to be […] general, instead of solitarily individual, in their origin.
- Whitney (1875), Pag. 151

The real effective reason of a given phonetic change is that a community, which might have chosen otherwise, willed it to be thus […].
- Whitney (1875), Pag. 73

The tendency of phonetic change is so decidedly toward the abbreviation and mutilation of words and forms that it has been, suitably enough, termed “phonetic decay.”
- Whitney (1875), Pag. 74