English plurals and where they come from

There are a few rules for forming plural nouns in English, and many exceptions to this rule! Learners of a second language are often familiar with the exceptions and have to learn them individually, as painful as that is, but where do these exceptions come from? Is it random or is there a linguistic reason behind it? Let’s take a look at some examples.

How are plurals formed in English?

There are some basic rules for forming plurals in English. We know that most of the time, you add an -s (cat, cats), sometimes an -es (tax, taxes). And then there are the times a -y turns into an -ies (city, cities,) or an -f turns into a -ves (wolf, wolves). An -o turns into an -oes (tomato, tomatoes), and an
-is turns into an -es (axis, axes). There are some other weird ones, like an -us turning into an -i (fungus, fungi), and an -on turning into an -a (phenomenon, phenomena). It might seem like a small issue, but getting these kinds of things right can make a big difference to how your English skills are perceived by your clients, colleagues or customers. Check out our seminars here if you think you need some extra help.

Regular vs irregular

It is important to note that there are exceptions to most if not all of these rules! There are also some nouns that don’t change at all in the plural – context is what will tell you what you need to know in these cases. There are so many of these in English because of the language’s roots. It has evolved a lot over time and been influenced by and borrowed from so many languages that a lot of inconsistent bits and pieces remain. We’ll look into a few irregularities below.

Goose/geese and moose/moose

The word “moose” did not enter the English lexicon until this language was widely spoken in North America (where moose are found), sometime in the 17th century. According to the Oxford Dictionary, it comes from Eastern Abnaki, a dialect of Algonquian, a Native American language spoken in Quebec and the surrounding areas. It keeps the same plural ending it had in its original language instead of adopting the normal plural rules for English nouns. “Goose” becomes “geese” just as “tooth” and “foot” become “teeth” and “feet” for a similar reason – because they are rooted in an ancient form of German and align more closely with that language’s pluralisation rules.

Mouse/mice and house/houses

The same applies to the mouse/mice conundrum. And sometimes, there is no special reason for it. “Mouse” and “house” both come from a German root, but they follow different pluralisation rules because they have had different paths through the English language. This is the nature of a language that is constantly changing, borrowing and adapting. Exception: when talking about an electronic mouse attached to your computer, it’s acceptable to use “mouses” for the plural!

Cactus/cacti and octopus/octopodes/octopi/octopuses

This one is a difference in the root languages of these words. The word “cactus” comes from Latin, and the English pluralisation of words like this with an -i is a remnant of the Latin rules. This is not a hard and fast rule anymore (English is full of inconsistencies) and some have been abandoned in common language (you don’t often hear or read “foci” or “syllabi”).

People often think “octopus” belongs with this group of words as well, but it actually has Greek roots. The rule of mimicking the root pluralisation (which would give us “octopodes”, although this is a very infrequent variation) wasn’t originally used, with various sources from the 19th century either adopting the more common Latin root rule of words ending in -us pluralised with -i (“octopi”) or opting for the English rule of pluralisation of adding an -es to words ending in “s” (“octopuses”). If you’re interested in the details, Merriam-Webster has published a very helpful summary of the friendly debate about the “correct” plural of “octopus”. It is possible that either “octopuses” or “octopi” will eventually win out as correct, because if a word is commonly used and understood, this should be the case. After all, English is a good example that languages are constantly evolving. But that’s a story for another blog post.

If you’re in any doubt about this or any other question to do with English, our experts at EnglishBusiness are always willing to help. Get in touch.

This post was written by

Rebecca Hill

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