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