phrase, partially assimilated
into English. The full phrase in French is "Plus ça change, plus c'est la meme chose," which translates as "The more things change
, the more things stay the same."
It's often used in a cynical sense to imply that although the outside surface appearance of things may appear to differ, underneath the system is basically the same.
If you want to impress someone with your stunning knowledge of French, the rough pronounciation is:
Ploo suh shonzh, ploo say la mem shozz