This paper concerns itself with how policy is made in democratic nations in order to secure equal language rights. The case study assessed is Aotearoa New Zealand's 2016 Maori Language Act and the process by which it passed into legislation. The paper draws on theories of public policy change, specifically the evidence-based policy approach, and examines the role of the language expert in light of Roger Pielke's [(2007). "The honest broker: Making sense of science in policy and politics." Cambridge: Cambridge University Press. doi:10.1017/CBO9780511818110] archetypes, in particular, the issue advocate and the honest broker. Two independent review groups' reports are analysed to understand whether their recommendations were acted upon. The analysis finds that there were similarities and differences in Te Paepae Motuhake and the Waitangi Tribunal's recommendations, in particular. whether language planning should be top-down or bottom-up. The paper concludes that the different expert roles and ideologies of the two review groups were both important in developing Aotearoa New Zealand's innovative dual-strategy Maori language policy. Such findings show that understanding how policy is made in democracies is important if language experts wish to turn argument and evidence into action to advance minority and particularly indigenous languages.