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