Translation:Is American a language?
I'd interpret it as just "American", since American English would be 미국 영어. That's what the sentence is implying.
To form the name of a language, you usually (but not always) add the suffix 어, which comes from the Chinese 語, meaning language, to the end of a country's name. Like so:
프랑스 (France) > 프랑수어 (French)
일본 (Japan) > 일본어 (Japanese)
한국 (Korea) > 한국어 (Korean)
미국 (America) > 미국어 (American)
Of course, there's no language called American (despite what some Americans might claim), but that's the point of the example.