§71. The Perfect Participle Base + suffix -IO as Abstract Noun

Of all ways to create abstract nouns from Latin verbs, the overwhelming favourite was the addition of the suffix -io to the perfect participle base (or less commonly to the present infinitive base). For example, from dicere, dictus (“speak”), Latin could create an abstract noun dict-io, dict-ionis, which meant “speech” (or “the act of speech,” “the process of speaking,” etc.). Notice that this is a perfectly regular 3rd declension noun, whose base is diction-. Here, then, is the explanation for all those -ion derivatives that we noticed in the last chapter. Historically, English forms in -ion can be traced back through Old French to medieval accusative forms like dictionem, which were prevalent in vulgar Latin at a time when the nominative forms had all but disappeared. For practical purposes, however, we can equate the English -ion spelling with the BASE form of Latin nouns in -io, -ionis.^[1] This is a valid historical approach, because the majority of the -ion forms came into Modern English after the Renaissance, drawn directly from Latin nouns on the analogy of the older -ion derivatives. New examples are still being coined today.

To the student of English vocabulary, this circumstance is nothing less than a godsend. Although you may never have stopped to think how many -ion nouns there are in our language, you can be sure that there are enough to keep you counting for hours on end. Almost without exception (ex-cept-io), they will have a Latin derivation (de-rivat-io), and that knowledge should be reason^[2] for great satisfaction (satis-fact-io)—perhaps even be an occasion (oc-cas-io) for exultation (ex-sultat-io). There can be few aspects of English etymology that are more dependable: virtually every -ion noun that you meet can now send you scurrying in search of a Latin perfect participle, whose meaning is almost guaranteed to unlock the semantic secrets of that English noun.

If you want to test that assertion (ad-sert-io), you can take another quick tour of the Latin verbs on Tables 9.1, 9.2, 9.3, and 9.4, applying the -ion test to the perfect participles. What you will now be uncovering is a series of Latin 3rd declension abstract nouns in -io, -ionis, probably the largest single category of Latin derivatives in English.