Règle correspondante
Practice Relating to Rule 100. Fair Trial Guarantees
Section H. Assistance of an interpreter
Switzerland’s Criminal Procedure Code (2007), as amended to 2012, which regulates the prosecution and adjudication by the federal and cantonal criminal justice authorities of offences under federal law, including war crimes, states: “Where a party to the proceedings does not understand the language of the proceedings or is unable to express himself adequately, the director of proceedings shall appoint an interpreter.” 
Switzerland, Criminal Procedure Code, 2007, as amended to 2012, Article 68(1); see also Article 158(1)(d).