For someone it's a tough task.However for other it's piece of cake.I had heard,that H.Schliman could have learned the next foreign language for 3 months.I can believe in it under certain conditions..if you learn for example French after English or Dutch after German but anyway to get solid knowleage,you need all your life.I've been learning English for 2 years,can read books,watch TV,but can't speak.Have no vocal practice at all.=)