If necessary, a transition period may be provided to enable legal experts to adapt and, in certain cases, simply put, to take French courses.
That being said, if the Prime Minister and the Government of Canada make it very clear that Supreme Court of Canada judges will now have to be bilingual, which will be provided for by an amendment to a piece of legislation, the legal experts will hear and understand the message. My friends are skilled enough, well trained and intelligent to adapt to the new rule, or even to do so fairly quickly.