In English in most cases it is very simple to form the plural form of a noun by adding “s” at the end of the noun.
With nouns that end in s, ss, ch, sh, zz, o or x, “es” must be added at the end of the noun with some exceptions.
Exceptions: stomach, monarch
Exceptions: radio, piano, zoo
But with singular nouns that end in “fe” or “f”, the plural ending changes into “ves” with some exceptions.
Exceptions: chief, belief, roof
For singular nouns that end in “y” preceded by a consonant, the final “y” changes into “ies” in the plural form.
But when the final “y” is preceded by a vowel, only “s” is added to make the noun plural.
The following nouns change in the plural form.
Here are some nouns that have the same singular and plural forms.
Some nouns exist only in the singular or plural form.