This article explores normative arguments for mandatory judicial bilingualism. It disentangles the links between the normative reasons advanced for mandatory bilingualism and the correlative level of French that should be expected of judges. To provide empirical anchoring, we construct a bilingualism score of Canadian Supreme Court justices composed of four indicators. The score shows that non-systematic assessments used so far like self-assessments, parliamentary hearings and media coverage are not reliable instruments to predict the level of use of French on the Supreme Court. Also, the score suggests that institutional dynamics have an impact worth studying in more depth. Ultimately, the measurement of functional bilingualism depends first on which linguistic capacity is being measured. This, in turn, depends on the normative reasons supporting the requirement of functional bilingualism. Instead of asking whether French should be mandatory upon appointment, it might be more productive to ask how much French should be required.
