As I said earlier, we are talking about the right to be heard and understood without the aid of an interpreter. So it could certainly be that judges may understand very well when litigants speak to them in an official language other than their own. But they might have difficulty speaking in that other languages. So, as you said, that person should still be bilingual enough to be able to ask clarification questions, if needed, in order to understand fully.
On May 4th, 2017. See this statement in context.