English has two grammatical categories of number. One is the singular, and the other is the plural. Many nouns in English have different singular and plural forms. When nouns are borrowed from other languages into English, the plural form in the source language comes with it (at least sometimes). However, not all languages have the same grammatical number categories that English has. I think that some don't decline at all for number. Some have more categories, like the dual and the trial[1]. If you import a noun from a language with more categories, do you use any different dual, trial, etc. forms that the noun has in the source language? What about if you import a noun from a language that doesn't have grammatical number? Do you decline it for number using English's "default" -s/-es scheme?

This is mostly or entirely contrived (currently, anyway).

  1. See http://en.wikipedia.org/wiki/Grammatical_number#Types_of_number
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    When we actually "import" a foreign word into English, we don't normally take account of any rules of grammatical number in the original language. Since the newly-imported word will be unfamiliar to native English speakers, they will treat it as a regular singular form, with a regular plural formed by adding -s/-es. Commented Jun 7, 2012 at 18:36
  • When you borrow a word, you don't borrow the entire grammar. The whole point of borrowing a word into English is to make it an English word, i.e. to make it obey the rules of English grammar. Of course there are always exceptions, but they are just that: exceptions. Irregular plurals are called irregular for a reason.
    – RegDwigнt
    Commented Jun 7, 2012 at 18:38
  • I voted to close as Too Localised, but in fact it should have been as a duplicate of Should nouns borrowed from Japanese be pluralized? Commented Jun 7, 2012 at 18:52
  • Um, you don’t mean declining nouns, but inflecting them. English has only two noun declensions: the unmarked form sometimes called nominative, and the possessive or genitive case. Pronouns have a few more. The point is that declension is about case.
    – tchrist
    Commented Jun 7, 2012 at 19:18
  • 2
    @tchrist, since we're already fighting about definitions: Some would argue that English nouns don't have a genitive form since 's is a clitic, i.e. it works on the phrase level, not the lexical level. It's "The queen of England's mother", not "The queen's of England mother".
    – dainichi
    Commented Aug 9, 2012 at 15:07

2 Answers 2


td,dr: Just use English rules — unless nobody else does. Then do whatever they do.

Perhaps the best rule is to ignore the language of origin that we pinched the newly borrowed word from and just use the same basic English rules for all inflections (usually noun plurals), as though it were fully naturalized into English. It’s certainly the easiest rule to remember, since you don’t have to learn the inflectional morphology of dozens of donor languages that way.

The truth is that it depends in part on how well assimilated the word is into English, and what the tradition is in the particular domain where that word is being used. Sometimes more than one version of a plural inflexion exists, such as both the English indexes and the Latin indices for the noun index, where mathematics tends to use the more conservative form.

Greek and Latin loanwords used in science and other technical disciplines often conserve their classical plurals. Some are now relatively common words like species and series, which due to their Latin origin (and perhaps also other phonologic factors serve as both the singular and the plural of each. So too does French chassis, although at least that one has a pronunciation difference between one chassis and two chassis.

Other terms with non-English plurals whose special Latin or Greek plural forms may not always be observed outside of technical writing include such singular/plural pairs as genus/genera, antenna/antennae, vertebra/vertebrae, mare/maria, thesis/theses, crisis/crises, emphasis/emphases, taxon/taxa, mythos/mythoi, dictum/dicta, paramecium/paramecia, phenomenon/phenomena, penis/penes, clitoris/clitorides, crysalis/crysalides, octopus/octopodes, fungus/fungi, nucleus/nuclei, radius/radii, criterion/criteria, matrix/matrices, cicatrix/cicatrices, larynx/larynges, stigma/stigmata — and many, many more.

Some exotic inflections seem more resistant to naturalization than others, such as with crisis > crises and emphasis > emphases. I don’t know why that should be. Loanwords that start out with classical inflections often lose them as we become more used to them. For example, the OED observes that specimina was fairly common as the plural of specimen during the latter half of the 17th century. However, the “special” plural form specimina instead of specimens is now so vanishingly small as to be virtually non-existent; you now only find it, if ever, in highly technical treatises on biology or typography.

You also sometimes see special plurals from French like plateaux, châteaux, and tableaux, or from Italian like mafiosi, tempi, or paparazzi. For whatever reason, non-English plurals for words coming from languages other than Latin or Greek don’t tend to last as long as the truly classical ones sometimes do. My own theory is that this is because compared to your average joe, writers in the sciences are not only more “precisionist” in their writing, they also are more likely to have studied Latin (and sometimes Greek) in their own studies.

It just depends on the field, though. For example, in computational linguistics the word corpus comes up all the time, meaning a body or collection of texts. In that domain, the expected form of the plural is the Latin one, so you have several corpora. However, we do not (to my knowledge) use the Latin genitives unless we are forming the species name of a particular taxon. So the possessive of the singular corpus is simply corpus’s in English instead of the Latin genitive singular corporis, and the plural possessive is corpora’s in English instead of the Latin genitive plural corporum. (Again, taxa are excepted, but those aren’t really English away; they’re “modern” Latin.)

Now and then you find some imported German nouns retain their German plurals for a little while, depending on the field. John Maynard Keynes actually used Spielräume for a particular philosophical term, being the German plural of Speilraum. Or when talking about the semi-autonomous local governmental units of Germany or Austria, each of which is a Land, you may see English writers using Länder for several of these. But these are markedly foreign; they are unassimilated imports. You can tell a German noun is on the road to being more fully Englished as soon as it loses its initial capital, as we see people writing zeitgeist in English instead of Zeitgeist. If that needed to be made plural, I would not be surprised to encounter the uncapitalized version to be the Englished zeitgeists, as it stands out rather less than writing Zeitgeister would.

The OED attests hundreds of different singular-to-plural irregulars for imports, but most of these don’t last long in English. It might have been bruschetta/bruschette and pannino/pannini right at the start, but those didn’t lost long, such now people look at you funny if you speak of “a graffito” in the singular, and it is not uncommon to get “double” plurals, like “two panninis”.

Just use English rules on loanwords’ plurals — unless you’re working with one that is expected to retain its irregular form. Those you should be able to find in a dictionary.

And the plural of virus is viruses. Always. :)

  • "phenomenon/phenomenon?"
    – Alex B.
    Commented Jun 7, 2012 at 20:09

The best bet in general is to treat most imported words as English words. Using "fora" rather than "forums" (or "stadia" or "penes", etc.) comes across as affected and strained. The exception would be in academic, mathematical, medical, scientific and technical contexts, which have their own conventions. Beware of confusing plurals and possessives. The Latin plural of "opus" is "opera"; the English plural is "opuses". The possessive is "opus's" and the English plural possessive is "opuses'". It is better, however, unless you are talking about musical compositions using technical terms ("Opuses 90-97 of J. S. Bach were written during a trip to Berlin" or the like), just to say "works".

For formerly foreign words that are now thoroughly integrated as English words, use English plurals. In technical or academic work, follow the conventions of the field. In ordinary conversation and correspondence, don't force words that still seem un-English in, except where it improves clarity or is necessary in context. In such relatively informal settings, use English plurals unless the foreign plural has been thoroughly integrated as well (as in "criteria" rather than "criterions").

  • Welcome to ELU. +1 for this valuable answer! Commented Sep 28, 2014 at 15:42

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