code: function stemPluralWord(plural_word){
      var matches = plural_word.match(/^(.*)-(.*)$/);
      if(!matches){
          return plural_word;
      }
      words = [matches[1], matches[2]];
  
      //malaikat-malaikat-nya -> malaikat malaikat-nya
      suffix = words[1];
      suffixes = ["ku", "mu", "nya", "lah", "kah", "tah", "pun"];
      matches = words[0].match(/^(.*)-(.*)$/);
      if(suffixes.indexOf(suffix) != -1 && matches){
          words[0] = matches[1];
          words[1] = matches[2] + '-' + suffix;
      }
  
      //berbalas-balasan -> balas
      rootWord1 = stemSingularWord(words[0]);
      rootWord2 = stemSingularWord(words[1]);
  
      //meniru-nirukan -> tiru
      if(!find(words[1]) && rootWord2==words[1]){
          rootWord2 = stemSingularWord("me" + words[1]);
      }
      if(rootWord1==rootWord2){
          return rootWord1;
      }
      else{
          return plural_word;
      }
  }
docs: Stem for plural word