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