WordPress Accept-Language Utilities

A lean WordPress utility for parsing and working with HTTP Accept-Language headers. Built for multilingual sites, content negotiation, and language-based conditional functionality.

Features

• 🌍 Language Detection - Parse Accept-Language header with quality values
• 🎯 Best Match - Find the best language from your available translations
• 🔄 RTL Detection - Identify right-to-left language preferences
• 📊 Quality Values - Access preference weights for each language
• 🛠️ Normalization - Consistent locale formatting (en-US, de-AT)

Requirements

• PHP 7.4 or later
• WordPress 5.0 or later

Installation

composer require arraypress/wp-accept-language-utils

Usage

Basic Language Detection

use ArrayPress\AcceptLanguageUtils\AcceptLanguage;

// Get the user's primary preferred language
$primary = AcceptLanguage::get_primary();
// Returns: "en-US", "de", "fr-CA", etc.

// Get just the language code (without region)
$language = AcceptLanguage::get_primary_language();
// Returns: "en", "de", "fr"

// Get the region code
$region = AcceptLanguage::get_primary_region();
// Returns: "US", "CA", "GB", or null

Finding Best Match

// Your site's available languages
$available = ['en', 'de', 'fr', 'es'];

// Find the best match for the user
$best = AcceptLanguage::get_best_match( $available, 'en' );
// Returns best match or 'en' as default

// WordPress integration
$locale = AcceptLanguage::get_best_match( 
    get_available_languages(), 
    'en_US' 
);

Checking Language Acceptance

// Check if user accepts a language
if ( AcceptLanguage::accepts( 'de' ) ) {
    // Show German content option
}

// Exact match only (e.g., en-US vs en-GB)
if ( AcceptLanguage::accepts( 'en-US', true ) ) {
    // US English specifically accepted
}

// Get the quality/preference value (0.0 to 1.0)
$quality = AcceptLanguage::get_quality( 'fr' );
// Returns: 0.8, 1.0, etc. or null

RTL Detection

// Check if user prefers RTL language
if ( AcceptLanguage::is_rtl() ) {
    wp_enqueue_style( 'theme-rtl', 'css/rtl.css' );
}

Parsing the Full Header

// Get all languages with quality values
$languages = AcceptLanguage::parse();
// Returns: ['en-US' => 1.0, 'en' => 0.9, 'de' => 0.8]

// Get all language codes (without quality values)
$all = AcceptLanguage::get_all();
// Returns: ['en-US', 'en', 'de']

// Get unique base languages only
$unique = AcceptLanguage::get_languages();
// Returns: ['en', 'de'] (no duplicates)

Utility Functions

// Normalize a language code
$normalized = AcceptLanguage::normalize( 'EN-us' );
// Returns: "en-US"

// Extract language from locale
$lang = AcceptLanguage::extract_language( 'en-US' );
// Returns: "en"

// Extract region from locale
$region = AcceptLanguage::extract_region( 'en-US' );
// Returns: "US"

Common Use Cases

Multilingual Content Switching

function get_user_content_language() {
    $available = [ 'en', 'de', 'fr', 'es', 'ja' ];
    
    // Check for user preference cookie first
    if ( isset( $_COOKIE['preferred_lang'] ) ) {
        return $_COOKIE['preferred_lang'];
    }
    
    // Fall back to Accept-Language header
    return AcceptLanguage::get_best_match( $available, 'en' );
}

Conditional Asset Loading

function enqueue_language_assets() {
    // Load RTL stylesheet if needed
    if ( AcceptLanguage::is_rtl() ) {
        wp_enqueue_style( 'theme-rtl', get_template_directory_uri() . '/rtl.css' );
    }
    
    // Load language-specific scripts
    $lang = AcceptLanguage::get_primary_language();
    $script = "js/i18n/{$lang}.js";
    
    if ( file_exists( get_template_directory() . '/' . $script ) ) {
        wp_enqueue_script( 'theme-i18n', get_template_directory_uri() . '/' . $script );
    }
}
add_action( 'wp_enqueue_scripts', 'enqueue_language_assets' );

E-commerce Localization

function set_store_locale() {
    $available = [
        'en-US' => 'USD',
        'en-GB' => 'GBP', 
        'de-DE' => 'EUR',
        'ja-JP' => 'JPY',
    ];
    
    $locale = AcceptLanguage::get_best_match( array_keys( $available ), 'en-US' );
    
    return [
        'locale'   => $locale,
        'currency' => $available[ $locale ],
    ];
}

Language Preference Logging

function log_visitor_language( $order_id ) {
    $order = wc_get_order( $order_id );
    
    $order->update_meta_data( 'browser_language', AcceptLanguage::get_primary() );
    $order->update_meta_data( 'browser_languages', implode( ', ', AcceptLanguage::get_all() ) );
    $order->save();
}
add_action( 'woocommerce_new_order', 'log_visitor_language' );

Helper Functions

Global functions are available for common operations:

// Get primary language
$lang = get_accept_language();

// Find best match from available
$best = get_preferred_language( ['en', 'de', 'fr'], 'en' );

// Check if language is accepted
if ( accepts_language( 'de' ) ) {
    // ...
}

// Check RTL preference
if ( is_rtl_language() ) {
    // ...
}

API Reference

Method	Description	Returns
get_header()	Get raw Accept-Language header	?string
get_primary()	Get preferred language code	?string
get_primary_language()	Get language without region	?string
get_primary_region()	Get region code only	?string
parse()	Parse header to array with quality	array
get_all()	Get all language codes	array
get_languages()	Get unique base languages	array
accepts( $lang, $exact )	Check if language accepted	bool
get_quality( $lang )	Get quality value for language	?float
get_best_match( $available, $default )	Find best match	?string
is_rtl()	Check if primary is RTL	bool
normalize( $code )	Normalize language code	string
extract_language( $locale )	Extract language from locale	string
extract_region( $locale )	Extract region from locale	?string
get_common_languages( $as_options )	Get language list for dropdowns	array

Supported RTL Languages

Arabic, Hebrew, Persian/Farsi, Urdu, Yiddish, Pashto, Sindhi, Uyghur, Kurdish (Sorani), Divehi

License

GPL-2.0-or-later

Support

• Documentation
• Issue Tracker