If a noun ends in -eau?
Add an x to the end.
If a noun ends in -eu?
Add an x to the end.
Exceptions:
Blue = Blues
Pneu = Pneus
If a noun ends in -ou?
Add an x to the end.
If a noun ends in -au?
Add an x to the end.
If a noun ends in -œu?
Add an x to the end.
If a noun ends in -ail?
Replace -ail with -aux.
If a noun ends in -al?
Replace -al with -aux.
Exceptions:
Festivals; carnavals; bals
No additional -S if?
The noun ends in -x, -s, or -z.
What nouns have an -x as a plural?
Nouns that end in -eau, -eu, -ou, -au, and -œu.
What nouns have an -aux as a plural?
Nouns that end in -ail or -al.
What other part of speech has the same plural rules?
Adjectives.