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Irregular plural nouns: mutant plurals

English has seven MUTANT PLURALS—irregular nouns that change their vowel sounds when they go from singular to plural. Because of weird language reasons, they don't form plurals normally. Those nouns are "foot", "woman", "man", "tooth", "goose", "mouse", and "louse". They become "feet", "women", "men", "teeth", "mice", and "lice".

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  • hopper cool style avatar for user Jett Burns
    Why isn't leaf considered a mutant plural? It changes from leaf to leaves, whats the difference?
    (51 votes)
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  • blobby green style avatar for user Teresa Bergman
    It's funny that the plural of spouse is not spice!
    (40 votes)
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  • blobby green style avatar for user Pratyaksh Hariysh Talekar
    Hey David,I was just wondering that why do Roman people use letters as numbers? Please answer me.
    (9 votes)
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    • duskpin ultimate style avatar for user Polina Vitić
      Roman numerals weren't actually letters: they were symbols used to represent numbers. The fact that they look like letters is considered a coincidence.

      Many people have suggested that it is helpful to think of the symbols as tally marks.

      For instance:
      1 - I
      2 - II
      3 - III
      4 - IV
      5 - V
      6 - VI
      7 - VII
      8 - VIII
      9 - IX
      10 - X
      11 - XI
      See how they are like tally marks?

      One of the limitations of Roman numerals was the lack of zero; another was that while addition and subtraction were easy, using Roman numerals made multiplication and division much more difficult.

      Arabic numerals (1 2 3 etc.) were first developed almost 2000 years ago in India. Arabic mathematicians adopted this system in the 9th century, and were able to make many important advances in mathematics, including the creation of the decimal system.

      Eventually, European mathematicians and scientists, who had been using Roman numerals for centuries, began using Arabic numerals instead. This became common practice around the year 1400 CE.

      Anyway, this little bit of history explains why we use numbers the way we do. It is really helpful to understand how Roman numerals work, because they still have some uses today.

      Some examples:
      - copyright dates for films and books (MMXIX)
      - hour markings on analog clocks & watches (I II III etc.)
      - Super Bowl championship numbers (in 2020 it will be LIV)
      - names of royals (Cleopatra VII Philopator)
      - also, names of non-royals (Hank Williams III)
      (32 votes)
  • sneak peak green style avatar for user Coding4el
    At and , David said '7', but aren't there nine?

    1. Child → Children
    2. Man → Men
    3. Ox → Oxen
    4. Woman → Women
    5. Mouse → Mice
    6. Foot → Feet
    7. Louse → Lice
    8. Goose → Geese
    9. Tooth → Teeth
    (12 votes)
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    • piceratops ultimate style avatar for user 24alanzi
      So, I do see were you are going with that. But if you were to put child in a sentence, lets say,"The child jumped onto the ladder." If you were to replace child with children, it would become,"The children jumped onto the ladder." So, hopefully you noticed, the tense of the verb and subject did not change, as the regular 7 would have.
      (10 votes)
  • scuttlebug green style avatar for user Uma
    Foot, tooth and goose - O becomes E
    Woman and man - A becomes E
    Mouse and louse - OUSE(us) becomes ICE

    They do have groups! Just very small ones.
    (12 votes)
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  • duskpin ultimate style avatar for user Nia
    why isn't person one of the seven words
    (9 votes)
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    • scuttlebug green style avatar for user Uma
      Because English is a weird language. There is old English and new English and slang English, and about seven other Englishes which don't have a fixed name. (To be fair, I don't know if there is such a thing as slang English, either, but you know what I mean.) And the grammar rules can't keep pace with all of it. English is a functional language and that necessarily means that there will be a lot of slip-ups.

      Also because person is irregular, but not the same type of irregular as the mutant plurals. It has both persons and people as its plurals.
      (6 votes)
  • male robot hal style avatar for user MYTHIC
    Are there really only 7 mutant plurals in the english language?
    (7 votes)
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  • blobby green style avatar for user Omi
    Just curious,
    Am I the only one who thinks that the way of pronouncing Woman and the way of pronouncing Women isn't the same?
    (sorry if it's a silly question).
    (4 votes)
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  • starky sapling style avatar for user Alice Wise
    What's a Louse?
    (2 votes)
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  • blobby green style avatar for user tobirose2007
    what about the word Pegasus shouldn't it be considered a mutant noun
    (3 votes)
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Video transcript

- [Voiceover] Hello, grammarians. Welcome to Irregular Plurals, Part IV. The Mutant Plurals. (moans) Yes friends, these words have mutant superpowers in that they can transform weirdly and obnoxiously, not obeying any other rules of English pluralization. But here's the cool thing. There are only seven words that behave this way. What way? I'll explain by writing all of them down. The words are foot, woman, man, tooth, goose, mouse, louse. Looks pretty straightforward, right? The thing about these words is that none of them take s as a plural. So the plural of foot is not foots, the plural of woman is not womans, the plural of tooth is not tooths. The reason these are called mutant plurals is because the vowel sound, the ooh, or the uh, or the ah, or the ooh, or the ooh, or the ou, or the ou, turns into a different sound, turns into a different vowel sound. So the plural of foot is not foots, but feet. The plural of woman is not womans, but women. The plural of man is not mans, but men. The plural of tooth is not tooths, but teeth. The plural of goose is not gooses, but geese. The plural of mouse is not mouses, but mice. And the plural of louse is not louses, but lice. You can see that mouse and louse actually change their end spelling as well from se to ce. Even though it's the same sound, louse, lice, for whatever reason, just from some quirk of our spelling history, not only do we change the vowels used here, we also change the consonants you say. Why is this the case? I'm so glad you asked. I'm going to save that for another video. In the meantime, just these seven words. One, two, three, four, five, six, seven, are the only words in English that behave this way. So you're in luck. This is a handful of words to memorize. And provided you're not borrowing any one else' hats, ideally you won't have to worry about lice very often. That's my hope. You can learn anything. David out.