What rules of thumb govern when to pluralise a foreign word as it should be in the original language and when it should be pluralised as an English word?

For example, you'd get some funny looks using "octopodes" or "lemmata" in normal conversation. (I don't know what contexts would allow mention of cephalopods and mathematics, but you know...)


General rule of thumb is that words which obviously originate from Latin and are not in frequent use might be given the Latin plural (e.g. alumnus/alumni with 22m Google hits). More common Latin words usually have an English plural (e.g. campus/campuses 122m; bonus/bonuses 108m).

For languages other than Latin (and perhaps French), English plural is almost always used, even for rare words (e.g. klutz 5m), except where plural is the predominant or only form (e.g. spaghetti).

This is completely unscientific, my intuition as a native speaker (American). Counterexamples are welcome.

  • I guess the question then is: "what counts as frequent use?" – Seamus Sep 6 '10 at 10:01
  • Often when coming from a language with no plurals, English won't pluralise either eg "The Seven Samurai". – Joel Roberts Oct 7 '16 at 0:26

It doesn't seem to me there are any rules of thumb for how to pluralize a foreign word.

The New Oxford American Dictionary reports that both lemmata, and lemmas are the plural of lemma. If I check on the Corpus of Contemporary American English, and I search for lemma*, I notice that

  • The word is used mostly in academic contexts.
  • In an academic context, the word lemmata is never used; in one case, the word used is lemmae.

    Other examples of lemmae held to be doublets, and furnished with catchwords, but which actually occur three […].

If then I search for lemma* in the Corpus of Historical American English, I notice that the word lemmata is used for the first time in the 1900s; for the other years, before or after, the CoHA doesn't report the word lemmata.

For octopus the NOAD reports that

The standard English plural of octopus is octopuses. However, the word octopus comes from Greek, and the Greek plural form is octopodes. Modern usage of octopodes is so infrequent that many people mistakenly create the erroneous plural form octopi, formed according to rules for Latin plurals.

Looking for octop* in the CoCA, I found out that

  • Words starting with octop are used with higher frequency in fiction and magazines.
  • In magazines, where words starting with octop are used with an incidence of 3.14 per million, I find only three examples of text using _octopodi; in the other cases, the used words are octopus and octopuses. I also found the word octopusan, and Octopussy (the title of a James Bond movie).

    If such a quality as intelligence can arise both in human beings and in the octopusan eight-armed sea animal without a bone in its body, then perhaps there is a course and […].

A search for octop* in the CoHA gives the following results:

  • Octopodi is used through the years with a variable incidence.
  • Octopodes is used in one case.

    In addition to being unspellable (octopuses, octopusses, octopoi, octopi, octopodes?), it conjured up every old horror cliche.

  • There are a few instances of words like octopoid, and octopodous.

    Barney said, struggling free of the perfumed octopoid embrace, "just take your client aside for a moment then I'll be […]".
    […] Philharmonic Society, which, as I have already pointed out, is within the octopodous grip of the BBC even to the extent of having to satisfy that totalitarian body […].

  • There is way too much about octopuses in this answer. – delete Sep 5 '10 at 0:27
  • 4
    Tell me, O Octopus, I begs! Is those things arms or is they legs? I marvel at thee, O Octopus. If I were thou I'd call me Us. – Brian Hooper Sep 5 '10 at 6:39
  • 1
    Well, "lemmae" is definitely wrong. For the same reason "octopi" is. The word "lemmata" certainly is used. I've seen it used myself. CoHA searches for "lemma*" aren't going to turn up much before 1900 because before then the majority of mathematics research was done in German and before that French or Latin. – Seamus Sep 5 '10 at 15:06
  • I believe that mathematicians will generally understand lemmata, even though they don't usually use it. – Peter Shor Jun 10 '11 at 0:18

What rules of thumb govern when to pluralised a foreign word as it should be in the original language and when it should be pluralised as an English word?

I don't think there are any rules at all. For example "spaghetti" is a plural in Italian but we use it as an uncountable noun in English.

Going through a list of Japanese words which have come into English (note that Japanese has no notion of plurals, uncountables, etc.), I see mostly cases where English has put whatever it finds convenient onto the word: "kimono" -> "kimonos", "satsuma" -> "satsumas", "miso"/"tofu" -> uncountable, as well as formations of nouns into adjectives, like "nashi" -> "nashi pears", "samurai" -> "samurai warriors", "shika" -> "sika deer", etc. Words which are specific to learners of the language, like "kanji", tend to be used in English with plurals without "s", e.g. "Remembering the Kanji" rather than "remembering the kanjis".

It looks like English is grafting these words onto itself in whatever way it finds most convenient, with the foreign plural being restricted to those who wish to demonstrate their knowledge of the foreign language ("spaghetti were" type of usages).


I think Latin and French words are trickiest. The word cousin is French, but we have dropped the French variants for plural and gender, while we have retained it for fiancé and fiancée. Many native American words are spelled with French spelling conventions because French speakers used them before English speakers, but are pluralized as if they were English. Most words use Enlish rules, but some retain their variations such as alumni, alumnea, alumna.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.