Provided the Accused or the Witness if not understood the Court Language then the Court must take steps to interpret its Language by appointing a Translator, who is unbiased, yet, acceptable to both; Prosecution and the Accused.
Provided the Court knew the Language of the Accused or Witness the Magistrate himself can occupy a role of a Translator and reduced the translation in writing make the Accused / Witness read and or explained and then take latter signature.