code: function RuleSet(language) {
    var data = englishRuleSet;
    DEBUG && console.log(data);
    switch (language) {
      case 'EN':
        data = englishRuleSet;
        break;
      case 'DU':
        data = dutchRuleSet;
        break;
    }
    if (data.rules) {
      this.rules = {};
      var that = this;
      data.rules.forEach(function(ruleString) {
        that.addRule(TF_Parser.parse(ruleString));
      })
    }
    DEBUG && console.log(this.rules);
    DEBUG && console.log('Brill_POS_Tagger.read_transformation_rules: number of transformation rules read: ' + Object.keys(this.rules).length);
  }
docs: Constructor takes a language abbreviation and loads the right rule set