woman, women

man, men

child, children

person, people

foot, feet

tooth, teeth

wife, wives

mouse, mice

life, lives

fish, fish

sheep, sheep

knife, knives

calf, calves

shelf, shelves

leaf, leaves

loaf, loaves

wolf, wolves

thief, thieves

half, halves

scarf, scarves

fruit, fruit

goose, geese

ox, oxen

penny, pence

fish, fishes

louse, lice

deer, deer

salmon, salmon

trout, trout

grouse, grouse

series, series

means, means

species, species

erratum, errata

crisis, crises

phenomenon,
phenomena

stimulus, stimuli

thesis, theses

datum, data

index, indexes

index, indices

formula, formulae

formula, formulas

armchair, armchairs

bookcase, bookcases

court-martial,
courts-martial

passer-by, passers-by

mother-in-law,
mothers-in-law

woman doctor, women
doctors

manservant,
menservants

medium, media

criterion, criteria

oasis, oases

bureau, bureaux

chateau, chateaux

plateau, plateaux

stadium, stadia

stadium, stadiums