Why We Say 'Feet' Instead of 'Foots'

Khan Academy

This educational video dives deep into the fascinating etymology behind English's "mutant plurals"—the seven specific nouns that change their vowel sound to become plural (like foot/feet and mouse/mice) rather than adding an "s." Hosted by a grammarian and a linguist, the discussion traces these words back to their Proto-Germanic roots to explain the historical mechanics of language change. The video explores complex linguistic concepts including vowel harmony, umlaut mutation (or i-mutation), and the Great Vowel Shift. Through handwritten diagrams and clear examples comparing English to German and Dutch, the hosts demonstrate how ancient plural suffixes eventually influenced the root vowels of words, leaving behind the irregular forms we use today. For educators, this resource is an excellent tool for demystifying English grammar. It moves beyond rote memorization of irregulars to provide the "why" behind the rules. It connects language arts with history and anthropology, showing students that language is a living, evolving system rather than a static set of arbitrary rules.