The Complete Guide to English Spelling Rules

(^) Three of these words are in the process of change. The word advertise is now quite often spelled
advertize. If we are prepared to accept advert as a noun, then the verbs advertize and advertizing are
logically correct. The words franchise and merchandise are nouns. When they are used as verbs, the
spelling ought to be franchize and merchandize.
Note that some words that are spelled with ize do not belong in this category because the ize is not a
true suffix or because it is part of a diphthong:
(^) But there are two words that reverse the rule—prize and prise. Spelled with a z it is a noun, but
spelled with an s it is a verb.
There are about a dozen words that are spelled with ise that are even more anomalous because of their
various pronunciations:
(^) In review, we can see that the four suffixes can be reduced to two major groups. In the first and largest,
we have the words ending in ize. In the second, we have words that end in ise. These words may be
nouns, verbs, or adjectives, but the ise ending is almost never a suffix. There are very few true anomalies.
With advertize, franchize, finalize, and a few other words, it is interesting to note that the change in
spelling is toward the spelling rule, not away from it.