What Is a Foreign Plural in English Grammar?

How to use foreign plurals

University student studying in library
ML Harris / Getty Images

A foreign plural is a noun borrowed from another language that has kept its original plural form rather than adapt the usual English plural ending of -s.

Words borrowed from classical Greek and Latin have tended to keep their foreign plurals in English longer than most other foreign borrowings.

Examples of Foreign Plurals in English 

  • "Scientists divide the bacteria [singular, bacterium] into groups based on shape: spherical cells, which are labeled as cocci (sing., coccus); rod-shaped cells, called bacilli (bacillus); curved rods, known as vibrios; and spiral-shaped bacteria."
    (Sherman Hollar, A Closer Look at Bacteria, Algae, and Protozoa. Britannica Educational Publishing, 2012)
  • "This step-by-step guide to creating and analyzing linguistic corpora [singular, corpus] discusses the role that corpus linguistics plays in linguistic theory."
    (Charles F. Meyer, English Corpus Linguistics: An Introduction. Cambridge University Press, 2002)

Divided Usage

English is jokingly referred to as the thief of languages because it borrows so many words from other languages. But because other languages have their own grammar rules, which are often wildly different from English grammar rules, the conjugation and use of these foreign words aren't always clear. When it comes to foreign plurals they usually follow the rules of their origin language. For this reason, it can be helpful for those looking to improve their English skills or vocabulary to brush up on Greek and Latin prefixes and suffixes. 

"English has borrowed words from nearly every language with which it has come into contact, and particularly for nouns from Latin, Greek, Hebrew, and French, it has often borrowed their foreign plurals as well. But when loan words cease to seem 'foreign,' and if their frequency of use in English increases, they very often drop the foreign plural in favor of a regular English ​-s. Thus at any given time we can find some loan words in divided usage, with both the foreign plural (e.g., indices) and the regular English plural (e.g., indexes) in Standard use. And occasionally we’ll find a semantic distinction between the two acceptable forms, as with the awe-inspiring Hebrew cherubim and the chubby English cherubs."
(Kenneth G. Wilson, The Columbia Guide to Standard American English. Columbia University Press, 1993)

The Latin and Greek -a Plural

"Because of its exceptional divergence in form from all other patterns of English plural formation, the Latin and Greek -a plural has shown a tendency to be reinterpreted as a non-count form, or as a singular with its own -s plural. This tendency has progressed furthest in agenda and has met with varying degrees of acceptance in candelabra, criteria, data, media, and phenomena."

(Sylvia Chalker and Edmund Weiner, Oxford Dictionary of English Grammar. Oxford University Press, 1994)

Subject-Verb Agreement With Foreign Plurals

"Well-recognized foreign plurals require plural verbs if they do not represent a singular unit.

Your criteria for grading my report are unfair.

Criteria, the plural form of criterion, means 'standards of rules.' This word has origins in the Greek language. Phenomena, the plural of the Greek phenomenon, is another example of plural usage.

Her upper vertebrae were crushed in the accident.

The singular of the Latin-derived vertebrae is vertebra."
(Lauren Kessler and Duncan McDonald, When Words Collide, 8th ed. Wadsworth, 2012)