This question requires context. You are talking about a certain word and its plural form, but you haven't told us what that word is. Our psychic powers are much less than you imagine them to be.
Yourself-yourselves
vest
The spelling rule of changing a final "f" to "v" and adding "es" when making a noun plural helps ensure proper pronunciation. When you add an "s" to words that end in "f," often the pronunciation becomes awkward, so changing it to "v" helps maintain the sound of the word.
Add -s to most nouns. Add -es to nouns ending in s, x, z, ch, or sh. Change -y to -i and add -es for nouns ending in consonant + y. Change f or fe to v and add -es. Memorize irregular plural forms like children, mice, and teeth.
The rule for forming the plural of the noun 'elf' is to change the ending 'f' to a 'v' and add 'es'. The plural noun is elves.
Elephants is the plural of elephant. Some plurals are made by adding an s to them, some of them by es, some of them have f which change to v with es.
The plural of loaf is loaves. Some, but not all words ending in F change it to a V and add -es to form the plural (thief-thieves, hoof-hooves).
Warves... when a word with an "f" on the end is made plural it is changed to a "v" and add es Ex: wives
To make the singular nouns ending in f and fe plural, change f to v then add es. Examples: wife - wives thief - thieves
Some examples of words ending in 'f' and 'fe' that is changed to 'ves' to form the plural are:calf - calveshalf - halveself - elveshoof - hoovesknife - knivesleaf - leaveslife - livesloaf - loavesself - selvessheaf - sheavesshelf - shelvesthief - thieveswife - wiveswolf - wolves
Originally, the rule used to be that the f was always changes to a v, e.g. knife - knives and hoof - hooves. There is no longer any hard and fast rule. Roofs can be roofs or rooves (though you don't usually see the latter any more). Chief and chef always seem to be chiefsand chefs.
Yes, it is. You change f(e) into v(e) and add s similarly to half - halves; shelf - shelves, self - selves, leaf - leaves.