the best way to make codeigniter website multi-language. calling from lang arrays depends on lang session?

Have you seen CodeIgniter's Language library?

The Language Class provides functions to retrieve language files and lines of text for purposes of internationalization.

In your CodeIgniter system folder you'll find one called language containing sets of language files. You can create your own language files as needed in order to display error and other messages in other languages.

Language files are typically stored in your system/language directory. Alternately you can create a folder called language inside your application folder and store them there. CodeIgniter will look first in your application/language directory. If the directory does not exist or the specified language is not located there CI will instead look in your global system/language folder.

In your case...

• you need to create a polish_lang.php and english_lang.php inside application/language/polish
• then create your keys inside that file (e.g. $lang['hello'] = "Witaj";
• then load it in your controller like $this->lang->load('polish_lang', 'polish');
• then fetch the line like $this->lang->line('hello'); Just store the return value of this function in a variable so you can use it in your view.

Repeat the steps for the english language and all other languages you need.

Also to add the language to the session, I would define some constants for each language, then make sure you have the session library autoloaded in config/autoload.php, or you load it whenever you need it. Add the users desired language to the session:

$this->session->set_userdata('language', ENGLISH);

Then you can grab it anytime like this:

$language = $this->session->userdata('language');

In the controller add following lines when you make the cunstructor

i.e, after

parent::Controller();

add below lines

    $this->load->helper('lang_translate');
    $this->lang->load('nl_site', 'nl'); // ('filename', 'directory')

create helper file lang_translate_helper.php with following function and put it in directory system\application\helpers

function label($label, $obj)
{
    $return = $obj->lang->line($label);
    if($return)
        echo $return;
    else
        echo $label;
}

for each of the language, create a directory with language abbrevation like en, nl, fr, etc., under system\application\languages

create language file in above (respective) directory which will contain $lang array holding pairs label=>language_value as given below

nl_site_lang.php

$lang['welcome'] = 'Welkom';
$lang['hello word'] = 'worde Witaj';

en_site_lang.php

$lang['welcome'] = 'Welcome';
$lang['hello word'] = 'Hello Word';

you can store multiple files for same language with differently as per the requirement e.g, if you want separate language file for managing backend (administrator section) you can use it in controller as $this->lang->load('nl_admin', 'nl');

nl_admin_lang.php

$lang['welcome'] = 'Welkom';
$lang['hello word'] = 'worde Witaj';

and finally to print the label in desired language, access labels as below in view

label('welcome', $this);

OR

label('hello word', $this);

note the space in hello & word you can use it like this way as well :)

whene there is no lable defined in the language file, it will simply print it what you passed to the function label.