Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
REGULAR
is of course an adjective whose basic meanings are “usual, customary, evenly spaced or timed, and normal,” but in this book it has a specialized grammatical sense as well, “by rule or generalization”: Regular English plurals of nouns are formed by adding an s, a z, or an iz sound at the end of the word, as in pots, bags, and judges.
