40 percent of the estimated 6,700 languages spoken around the world are in danger of disappearing. Most of these languages are indigenous languages, which embody complex systems of knowledge developed and accumulated over thousands of years. The disappearance of these languages often means this knowledge is lost forever. As the world marks the International Year of Indigenous Languages, we sat down with the UN Special Rapporteur on the Rights of Indigenous Peoples to talk about why she views culture as crucial to the fight for indigenous rights.