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