Most nouns ending in -o add -es to form the plural (with some exceptions like photo/photos).
So is regular. It follows the -es Addition rule.
Use plural verbs: "The soes are ready" (not "is ready").
Yes. The plural soes is standard across all English variants.
The word so follows the standard English pluralization rule. When forming the plural, so becomes soes. This follows the -es Addition pattern, which is one of the most common plural rules in English.
Understanding why so becomes soes helps with spelling and pronunciation. Most nouns ending in -o add -es to form the plural (with some exceptions like photo/photos).
When using soes in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The soes are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.