1 Answer. This is a throwback to Old English. The “f” would be pronounced like a “v” if it was between two vowels. For example, the word for heaven was heofon and would have been pronounced something like “hayovon” (Sorry, no IPA).

Usually, when a word ends in ‘f’ or ‘fe’ we change the ‘f’ to ‘v’ and add ‘es’ or ‘s’ to make it plural. Make plurals from these singular nouns.

The ves ending should be added to form plural nouns when the noun ends in f or fe.

4 If the noun ends with ‑f or ‑fe, the f is often changed to ‑ve before adding the -s to form the plural version. 5 If a singular noun ends in ‑y and the letter before the -y is a consonant, change the ending to ‑ies to make the noun plural.

To make a plural of a word ending in -f, change the f to a v and add es. Similarly, if a word ends in -fe, change the f to a v and add an s. The result for both types is a plural that ends in -ves….Nouns ending in -f and -fe.

The ves ending should be added to form plural nouns: When the noun ends in f or fe.

There are two rules for making the plural form of nouns that end with y: If a vowel comes before the Y, add an S. If a consonant comes before the Y, you drop the Y and add an “ies.”

For nouns that end in consonant + -y, change the “y” to “-ies” to make them plural. The vowels in English are: a, e, i, o, u, and sometimes y. So, if a noun has a consonant + -y ending, we change just the last letter to -ies. This creates a brand new plural word.

Y as a long I: The letter y makes the long sound of i when it comes at the end of a short word that has no other vowel. Examples: cry, try, my, fly, by, hi.