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