According to the OED and paraphrased from the 1989 edition — arguably before spellcheckers were widespread; the use of -ize, for instance, is dependant on the root of the word. Words that stem from Greek, with the transitive sense of ‘make or conform to, or treat in the way of, the thing expressed by the derivation’, or ‘to act some person or character, do or follow some practice’. Words formed (in French or English) on Latin adjectives and nouns (esp. on derivative adjectives in -al, -ar, -an, etc.), mostly with the transitive sense. Words from later sources. Words formed on ethnic adjectives, and the like, chiefly transitive but sometimes intransitive. Words formed on names of persons, sometimes with the intransitive Greek sense of ‘to act like, or in accordance with’. From names of substances, chemical and other; in the transitive sense of ‘to charge, impregnate, treat, affect, or influence with’.