LINUX: Weird characters when you compile

Why are there weird characters when I compile:

test.cpp: In function âint main()â:
test.cpp:7: error: âcoutâ was not declared in this scope
test.cpp:7: error: âendlâ was not declared in this scope

It's normal if you don't set the environment variable e.g.

export LANG=C

source(s):
http://gcc.gnu.org/ml/gcc-help/2006-08/msg00179.html