Yes, victims of National Socialist denationalization measures and their descendants have the right to be renationalized in line with Article 116 (2) of the Basic Law even if this means multiple nationality. There is no need to prove knowledge of the German language. Nevertheless it is examined whether the German nationality of the ancestor could have been lost for reasons unrelated to National Socialism. Were this the case, the descendants would have no right to German citizenship.
For further advice, please contact the competent German mission covering your place of residence.
German missions abroad: Countries A to Z