for english: u do not need any exam to prove it, whereas ur english should be good enough to take courses as well as stages(in hospital) and pass school and diploma exams.
for french: one must pass the professional french exam held by OQLF or,
finish 3-year post secondary education in french school or,
pass the course of french,maternal language (in stead of second language) in any secondary school (including adult high school education).
the requirement of french language for both registered nurse(RN) and nurse's assistant(or LPN,RNA,CNA,LVN) are definitely the same thing.
Thanks for any corrections!