"Slang is a language that rolls up its sleeves, spits on its hands and goes to work."

slang (noun): a very informal kind of language, sometimes including bad language
roll up (verb): move up; fold up
sleeves (noun): the parts of your shirt that cover your arms
roll up your sleeves (expression): prepare to work or fight
spit (verb): forcibly eject saliva from your mouth
spit on your hands (expression): prepare to work or fight