It is very important to point out two other things. The individual may choose to change the language of the proceeding for the simple reason that his counsel is more comfortable in the other language. But, even if the proceeding is held in English, or French, in this case, don't forget that anyone appearing before a federal tribunal has the right to address the tribunal in the official language of his or her choice.
On December 16th, 2010. See this statement in context.