What is the correct way to reference language file?

In the new pages I am creating what is the proper way and place to reference the appropriate language file?

At the moment I have

include(DIR_WS_LANGUAGES . '/english/products_all.php'); 

in the template file (/includes/templates/template_default/templates/tpl_product_credential_default.php)

I'm sure this isn't correct as "english" shouldn't be hardcoded in like this.

Regards,

Chris V

venablc:

In the new pages I am creating what is the proper way and place to reference the appropriate language file?

At the moment I have

include(DIR_WS_LANGUAGES . '/english/products_all.php');

> 
> in the template file (/includes/templates/template_default/templates/tpl_product_credential_default.php)
> 
> I'm sure this isn't correct as "english" shouldn't be hardcoded in like this.
> 
> Regards,
> 
> Chris V

Try this:  (untested) 
```php
$template =  $GLOBALS['template_dir'];
include(DIR_WS_LANGUAGES . $template.'/products_all.php'); 

Cheers
Rod

/includes/templates/template_default/templates/tpl_product_credential_default.php

Not a core ZC file, so

1. What's it doing in /template_default/?
2. Who put it there?
3. What is its purpose?

Your business logic should be in the /includes/modules/pages/PAGE_NAME_HERE/header_php.php file.
And that's where the language files are loaded.

See the About Us addon for an example of adding your own custom page as you seem to be trying to do.
(You can skip the html_includes folder content if you're not needing the define-page part of it)