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