Hello, fellas. How is it going? In this session we will discuss irregular plurals. Most plural forms are made by adding an –s at the end of their singulars. Nevertheless, some plural nouns do not follow this rule.

1) Vowel change
man / men
woman / women
foot / feet
tooth / teeth
goose / geese
mouse / mice

2) Add –en
child / children
ox / oxen

3) Same as singular
deer / deer
fish / fish
people / people
salmon / salmon
sheep / sheep
trout / trout

4) -is / -es
analysis / analyses
axis / axes
crisis / crises
diagnosis / diagnoses
hypothesis / hypotheses
parenthesis / parentheses
synthesis / syntheses
thesis / theses

5) End in –a
bacterium / bacteria
curriculum / curricula
datum / data
phenomenon / phenomena
criterion / criteria

6) –us / -i
alumnus / alumni
bacillus / bacilli
cactus / cacti
fungus / fungi
nucleus / nuclei
radius / radii
stimulus / stimuli
syllabus / syllabi

Sources:
Grammarly, Plural Nouns: Rules and Examples, https://www.grammarly.com/blog/plural-nouns/
Deborah Phillips, Longman Complete Course for the TOEFL Test

Compiled and written by @fathrahman for @EnglishTips4U on Monday, January 7, 2019