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