Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Familiarity is regular. It follows the -ies Conversion rule.
Use plural verbs: "The familiarities are ready" (not "is ready").
Yes. The plural familiarities is standard across all English variants.
The word familiarity follows the standard English pluralization rule. When forming the plural, familiarity becomes familiarities. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why familiarity becomes familiarities helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using familiarities in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The familiarities are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.