Learning a language

Assuming you:
a) Have a good beginner's resource to give you the basic foundation (A solid textbook of some kind)
b) Have continual access to resources to practice the four areas of usage mentioned above (listening/reading/writing/speaking)
c) Have an absolute devotion to and interest in the particular language and culture
d) Have at least 3-7 uninterrupted hours a week to spend
e) Have the concentration and planning to make the above hours work
f) Don't expect to catch every single social custom and mannerism

I would say it is very feasible but definitely easier said than done.

Jam it back in, in the dark.