gistfile1.php

<?php

  /**
   * Router - virtual link
   */
  protected  function _initRoutes()
  {
      $front = Zend_Controller_Front::getInstance();
      $router = $front->getRouter();

      $dynamic = new Zend_Controller_Router_Route(
            '/en/:variable1',
            array(
                'controller' => 'variable1',
                'action'     => 'index'),
                array('variable1' => '^[a-zA-Z0-9_]*$')
            );

      $router->addRoute('dynamic', $dynamic);      

  }

?>

gistfile2.txt

1) Visit /en/test

2) Get error

string(9) "variable1"
string(5) "error"
An error occurred

Page not found