1 April 2002
English borrows words like no other language. All languages borrow words from others, but English is as close to a polyglot as any major language can be. While this borrowing adds to the richness and power of the language, it does present certain grammatical problems.
One of these problems is how to form plurals of borrowed words. Do you use the standard English plural of -s/-es? Or do you use the foreign plural?
In general, the rule is that when a word enters common use in English, use the English plural. If the word is still considered a foreign one, use the foreign plural. When in doubt, use -s/-es. Hence, it’s sopranos, not soprani, focuses, not foci, and forums, not fora.
But there are exceptions. It’s crises, not crisises, criteria, not criterions, and theses, not thesises. In some cases, both forms are acceptable as plurals. Both honorariums and honoraria are correct, as are millenniums and millennia. Gradually, the foreign plurals will be edged out of the language, but for now either can be used. How do you identify these words? Look up the proper plural forms in a dictionary.
In some cases both plurals are acceptable, but in different contexts. Sometimes the differentiation marks who is using the word. A botanist will say fungi, while general use prefers funguses. A zoologist or physician will say ova, most others will use ovums. Biologists use stimuli, but stimuluses is in general use.
In other cases, the differentiation marks different senses of the word. Groups of people are phalanxes, while finger and toe bones are phalanges. Protozoans are used to count individual organisms, while classes of those creatures are protozoa. Only in the context of religious miracles is it stigmata. In all other cases it’s stigmas. In music it’s staves, everywhere else it’s staffs.
Before using a foreign plural form, make sure that it is the proper plural. The proper Greek plural of octopus, for example, is octopodes, not octopi. In English, use octopuses as the plural. It’s viruses, not virii. This type of error is known as hypercorrection.
These rules apply to other languages, not just Latin and Greek. The proper French plural of bon mot is bons mots, but in English the plural is bon mots. In French it’s chaises longues, in English it’s chaise longues. In English it’s cul-de-sacs, not culs-de-sacs. When the words are not commonly used in English, they retain the original French plural. So it’s chargés d’affaires and bêtes noires.
So how does one keep all this straight? It’s actually very simple. Remember, the dictionary is your friend. Finding the proper plural form is simply a question of reaching over to the nearest bookshelf or clicking to a new website. (Don’t trust Microsoft spell checkers. They’re usually right, but software engineers are notorious for their linguistic inadequacies.) And when in doubt, use -s/-es.
