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