Nouns ending in -a (often Latin or scientific) add -e to form the plural.
Extra is regular. It follows the -ae Addition rule.
Use plural verbs: "The extrae are ready" (not "is ready").
Yes. The plural extrae is standard across all English variants.
The word extra follows the standard English pluralization rule. When forming the plural, extra becomes extrae. This follows the -ae Addition pattern, which is one of the most common plural rules in English.
Understanding why extra becomes extrae helps with spelling and pronunciation. Nouns ending in -a (often Latin or scientific) add -e to form the plural.
When using extrae in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The extrae are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.