je vous en prie = please, s`il vous plait = please (word-by word translation is "if this pleases you") Entres , je vous en prie . = Come in, please. Monsieur roche. s`il vous plait = Mr Roche, please. (depending on the context) (if you mark you question as english less french speaking people will see it and so - you will have less answers)

"Je vous en prie" means: 'Please do.' Verb 'prier' means to ask someone to do something. 'vous' is used addressing the second pronoun 'tu' for respect. Literally it would be: I beg you to do it' or " I ask you to do it". The translation into English is however: "Please, enter." " s'il te ( or vous) plaît " means: (literally) if it pleases you 'plaît' from verb 'plaire' ,which means (=être du goût de qn) ,In English ' to please, to be liked). "S'il vous plaît" as a polite form (formule de politesse) means 'please'. "Mr Roche, please?"