How long does it take an average american to learn a second language?

This depends on your age and what language you are trying to learn really. Think about it this way, when you were born, how long did it take you to learn English (or your native tongue)? About five years right? This also depends on a bunch of other different factors like how much you practice, your determination, and the fluency of the language your speaking. So really there is no real definite answer because all people are different, but if I were to say, I'd say about five years...

If the language its easy like the Spanish its take 2 year and if the language is hard like Arabic its take 3 or 4 years