In some cases, irregular plural nouns keep the same spelling except one or all of the vowels are swapped. Here are just a few examples: Tooth - teeth Man - men Woman - women Foot - feet Oasis - oases Goose - geese. Nouns that break standard spelling rules: there are irregular plurals that don’t follow the same spelling conventions as a lot of other nouns. A lot of different words fall under this category. Here’s a few examples that pupils might be likely to come across in day-to-day use: Louse -