What is the correct language format for American English?

The correct language format for American English is "en-US." In this format, "en" stands for English, and "US" specifies the country code for the United States. This distinction is important as it helps software and applications tailor their content appropriately based on regional language variations and usage.

The other options represent English variants in different countries. For instance, "en-UK" corresponds to British English, while "en-AU" refers to Australian English, and "en-CA" indicates Canadian English. Each of these formats is used to provide language support that aligns with the respective conventions, spelling, and usage of English in those regions.