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