Why is the plural of ‘moose’ not ‘meese’?
As fitting as it might sound, the plural of moose is not and has never been meese. And while it is tempting to switch out -oo- for -ee-, the plural of moose is simply moose (though you may occasionally see or hear the word mooses). This confusion is understandable if you consider the word goose, with its plural geese. Given that both are animals and that the two words (in their singular forms) rhyme with one another, it’s a bit confusing why they don’t share a plural change as well.
So why don’t we say meese?
The simple reason is that it’s a loanword. All nouns that are borrowed into English either form their plural with the standard plural ending –s (the vast majority), retain the plural ending of the donor language (e.g. phenomena, algae), or remain unchanged in the plural. It is also quite possible for the same noun to employ more than one of the above types of plural formation. The word moose has its origin in the Native American Algonquian language. Adopted into English by British settlers of North America in the early 17th century, it comes from the Eastern Abenaki word mos, which also appears in southern New England Algonquian languages, such as the Narragansett word moòs.
But why, then, do we say geese instead of goose, or gooses in the first place? After all, geese is an obvious exception to the standard plural in English. The reason goes back a millennium and a half to the beginnings of Old English and to a sound change known as mutation (or umlaut), defined as ‘a change in the sound of a vowel produced by partial assimilation to an adjacent sound (usually that of a vowel or semivowel in the following syllable)’.
All that linguistics background might sound pretty complicated, but what it boils down to is that goose was one of a relatively small closed set of nouns in Old English which formed their plural in this way (by change of stem vowel). The number of such nouns was never large, and it has grown smaller over the centuries, because the tendency has been for these nouns to take on more common plural endings (especially the now standard plural –s). However, beside goose, there are still a few of these nouns left in English today which retain the mutation plurals, including tooth (plural teeth) and foot (plural feet).
The curiosity of moose and meese is just one of several strange plurals dating from Old English. Other words with similarly confusing plurals include child, which transforms into the plural children, and man and woman, which swap out -a- for -e- in their plural form.
Back to the question that we started off with, why didn’t this mutation happen to moose? As mentioned above, moose entered English via the Algonquian language in the early 17th century, long after the Old English vowel changes had happened. Though vowel mutation in English had hardly faded into the background, the specific process that gave us feet and geese had already occurred hundreds of years beforehand.
For more difficult plurals, check out this post covering everything from bacteria to criteria.