language settings in command line and man pages

[Peter O. Fedichev]

Hello

I have to work on a linux box with french language set default. Two 
questions:
(i have root permissions there)
1) how to switch back to english in the command line?
2) how to make man pages english?
I understand that I must read man pages to find out the answers, but 
what if they all are in the language I don't understand? :)

thanks