Extra SEO module  can replace:
http://website.com/property/31/en/property_title with:

http://website.com/my-custom-slug.htm

This module is very server configuration
sensitive so no guarantee that will work on all servers.
But it is tested on https://www.a2hosting.com/refer/59624 and there works fine.

Guide to configure:

In application\config\cms_config.php add this lines:
$config['slug_enabled'] = TRUE;
$config['alt_enabled'] = TRUE;

Regarding nice SEO slugs:
and in slug.php you should change:
$script_folder = '/property-point/';
to your folder or use  '/' if your website was in root folder

additionaly, use htaccess_examples/slug.htaccess, move to www directory and rename to .htaccess

and in .htaccess you should change:
RewriteBase /property-point
to your folder name or leave only '/' if your website was in root folder.
mod_rewrite should be enabled without limitations on server for this...

In application\config\config.php you should have defined:
$config['index_page'] = 'index.php';