What are some best practices for handling language selection in PHP web development projects?

When handling language selection in PHP web development projects, it is best to store language translations in separate files or a database to easily switch between them. One common approach is to use a session variable to store the selected language and load the appropriate language file based on this variable.

// Start session
session_start();

// Check if language is selected
if(isset($_GET['lang'])){
    $_SESSION['lang'] = $_GET['lang'];
}

// Default language
$language = 'en';

// Check if language is set in session
if(isset($_SESSION['lang'])){
    $language = $_SESSION['lang'];
}

// Include language file
include 'languages/'.$language.'.php';