Ouch, my brother's mouses are biting my foots! Waaiiitt, that doesn't make sense. One mouse, two MICE, one foot, two FEET! Join us in this lesson as we learn about irregular plural nouns. Most plural nouns only require an S or ES at the end, but some words are rule breakers. We have to memorize plural nouns like feet, mice, children, or men. Can you think of any others? Trick question: what is the plural of fish?