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