discover changes of sound that have taken place in the growth of each. These changes are of two kinds which it is very important to distinguish.
The first kind of change happens unconsciously without the speakers of the language knowing that any change has happened at all. Thus Lat. rēgem became in French roi: and we find that the same change happened to Lat. ē in all words in which it stood in an accented syllable. The statement of any such change (in this case that “Lat. ē when accented became oi in French”’) is called a Phonetic Law. The loss of the -g- and of the -em of rēgem happened also through phonetic changes, or, as we say, ‘by Phonetic Laws.’
§ 11. Strictly speaking Phonetic Laws have no exceptions: that is to say, a phonetic change affects equally the same sound in all words existing in the language at the time, provided that the sound is under the same conditions in all the words. Thus Lat. -ē- became Fr. -oi- when the e was accented, as it was in Lat. rēgem (see § 85 (2)), but not otherwise. Thus Lat. mē, tē, sē, became Fr. moi, toi, soi, when they were emphatic and therefore accented, but Fr. me, te, se, when they were unaccented.
§ 12. But it often happens that words containing the sound affected by a particular phonetic change are introduced into a language (sometimes from being borrowed from another language) after the phonetic change has ceased or, as it is often stated, ‘after the Phonetic Law has expired.’
For example, the word kirk was introduced (or
