diff --git a/includes/locale.php b/includes/locale.php
index db2fd3f1..4e61d0b9 100755
--- a/includes/locale.php
+++ b/includes/locale.php
@@ -1,133 +1,41 @@
 <?php
 /**
- * Sets locale information for i18n support, with secure input validation.
+ * Sets locale information for i18n support, with validation
  *
- * Rudimentary language detection is performed via the browser.
- * Accept-Language returns a list of weighted values with a quality (or 'q') parameter.
- * A better method would parse the list of preferred languages and match this with
- * the languages supported by our platform.
- * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
- *
- * Uses $validLocales to mitigate OS Command Injection (CWE-78)
- * @see Vulnerability Report for JVN #27202136
+ * @see RaspAP\Localization\LocaleManager
  */
 
-// Set locale from POST, if provided and valid
-$validLocales = array_keys(getLocales());
-if (!empty($_POST['locale']) && in_array($_POST['locale'], $validLocales, true)) {
-    $_SESSION['locale'] = $_POST['locale'];
-    setcookie('locale', $_POST['locale'], time() + (86400 * 30), '/', '', false, true);
-}
+use RaspAP\Localization\LocaleManager;
 
-// Set locale from cookie or browser detection, if not already set in session
-if (empty($_SESSION['locale'])) {
-    if (isset($_COOKIE['locale']) && in_array($_COOKIE['locale'], $validLocales, true)) {
-        $_SESSION['locale'] = $_COOKIE['locale'];
-    } else {
-        $_SESSION['locale'] = detectBrowserLocale();
-        setcookie('locale', $_SESSION['locale'], time() + (86400 * 30), '/', '', false, true);
-    }
-}
-
-// Enforce only valid locale values in session
-if (!in_array($_SESSION['locale'], $validLocales, true)) {
-    $_SESSION['locale'] = 'en_GB.UTF-8';
-    // Update cookie with default locale
-    setcookie('locale', $_SESSION['locale'], time() + (86400 * 30), '/', '', false, true);
-}
-
-// Apply locale settings
-putenv("LANG=" . escapeshellarg($_SESSION['locale']));
-setlocale(LC_ALL, $_SESSION['locale']);
-bindtextdomain(LOCALE_DOMAIN, LOCALE_ROOT);
-bind_textdomain_codeset(LOCALE_DOMAIN, 'UTF-8');
-textdomain(LOCALE_DOMAIN);
+// Initialize locale manager
+$localeManager = new LocaleManager();
+$localeManager->initializeAndApply();
 
+/**
+ * Get all available locales
+ *
+ * @return array Associative array of locale codes to language names
+ */
 function getLocales(): array
 {
-    return [
-        'en_GB.UTF-8' => 'English',
-        'cs_CZ.UTF-8' => 'Čeština',
-        'zh_TW.UTF-8' => '正體中文 (Chinese traditional)',
-        'zh_CN.UTF-8' => '简体中文 (Chinese simplified)',
-        'da_DK.UTF-8' => 'Dansk',
-        'de_DE.UTF-8' => 'Deutsch',
-        'es_MX.UTF-8' => 'Español',
-        'fi_FI.UTF-8' => 'Finnish',
-        'fr_FR.UTF-8' => 'Français',
-        'el_GR.UTF-8' => 'Ελληνικά',
-        'id_ID.UTF-8' => 'Indonesian',
-        'it_IT.UTF-8' => 'Italiano',
-        'ja_JP.UTF-8' => '日本語 (Japanese)',
-        'ko_KR.UTF-8' => '한국어 (Korean)',
-        'nl_NL.UTF-8' => 'Nederlands',
-        'pl_PL.UTF-8' => 'Polskie',
-        'pt_BR.UTF-8' => 'Português',
-        'ru_RU.UTF-8' => 'Русский',
-        'ro_RO.UTF-8' => 'Română',
-        'sk_SK.UTF-8' => 'Slovenčina',
-        'sv_SE.UTF-8' => 'Svenska',
-        'tr_TR.UTF-8' => 'Türkçe',
-        'vi_VN.UTF-8' => 'Tiếng Việt (Vietnamese)'
-    ];
+    static $localeManager = null;
+    if ($localeManager === null) {
+        $localeManager = new LocaleManager();
+    }
+    return $localeManager->getLocales();
 }
 
+/**
+ * Detect browser locale from Accept-Language header
+ *
+ * @return string Detected locale code
+ */
 function detectBrowserLocale(): string
 {
-    if (empty($_SERVER['HTTP_ACCEPT_LANGUAGE']) || strlen($_SERVER['HTTP_ACCEPT_LANGUAGE']) < 2) {
-        return 'en_GB.UTF-8';
-    }
-
-    $acceptLang = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
-    $lang = strtolower(substr($acceptLang, 0, 2));
-
-    if ($lang === 'zh' && strpos($acceptLang, 'zh-TW') === 0) {
-        return 'zh_TW.UTF-8';
-    }
-
-    switch ($lang) {
-        case 'de':
-            return 'de_DE.UTF-8';
-        case 'fr':
-            return 'fr_FR.UTF-8';
-        case 'it':
-            return 'it_IT.UTF-8';
-        case 'pt':
-            return 'pt_BR.UTF-8';
-        case 'sv':
-            return 'sv_SE.UTF-8';
-        case 'nl':
-            return 'nl_NL.UTF-8';
-        case 'zh':
-            return 'zh_CN.UTF-8';
-        case 'cs':
-            return 'cs_CZ.UTF-8';
-        case 'ru':
-            return 'ru_RU.UTF-8';
-        case 'es':
-            return 'es_MX.UTF-8';
-        case 'fi':
-            return 'fi_FI.UTF-8';
-        case 'da':
-            return 'da_DK.UTF-8';
-        case 'tr':
-            return 'tr_TR.UTF-8';
-        case 'id':
-            return 'id_ID.UTF-8';
-        case 'ko':
-            return 'ko_KR.UTF-8';
-        case 'ja':
-            return 'ja_JP.UTF-8';
-        case 'vi':
-            return 'vi_VN.UTF-8';
-        case 'el':
-            return 'el_GR.UTF-8';
-        case 'pl':
-            return 'pl_PL.UTF-8';
-        case 'sk':
-            return 'sk_SK.UTF-8';
-        default:
-            return 'en_GB.UTF-8';
+    static $localeManager = null;
+    if ($localeManager === null) {
+        $localeManager = new LocaleManager();
     }
+    return $localeManager->detectBrowserLocale();
 }
 
diff --git a/src/RaspAP/Localization/LocaleManager.php b/src/RaspAP/Localization/LocaleManager.php
new file mode 100755
index 00000000..aa611902
--- /dev/null
+++ b/src/RaspAP/Localization/LocaleManager.php
@@ -0,0 +1,258 @@
+<?php
+
+/**
+ * Locale Manager class
+ *
+ * @description Manages locale/i18n functionality for RaspAP
+ * @author      Bill Zimmerman <billzimmerman@gmail.com>
+ * @license     https://github.com/raspap/raspap-webgui/blob/master/LICENSE
+ */
+
+namespace RaspAP\Localization;
+
+class LocaleManager
+{
+    private string $locale;
+    private const DEFAULT_LOCALE = 'en_GB.UTF-8';
+    private const COOKIE_LIFETIME = 86400 * 30; // 30 days
+
+    /**
+     * Constructor
+     */
+    public function __construct()
+    {
+        $this->locale = self::DEFAULT_LOCALE;
+    }
+
+    /**
+     * Get all available locales
+     *
+     * @return array Associative array of locale codes to language names
+     */
+    public function getLocales(): array
+    {
+        return [
+            'en_GB.UTF-8' => 'English',
+            'cs_CZ.UTF-8' => 'Čeština',
+            'zh_TW.UTF-8' => '正體中文 (Chinese traditional)',
+            'zh_CN.UTF-8' => '简体中文 (Chinese simplified)',
+            'da_DK.UTF-8' => 'Dansk',
+            'de_DE.UTF-8' => 'Deutsch',
+            'es_MX.UTF-8' => 'Español',
+            'fi_FI.UTF-8' => 'Finnish',
+            'fr_FR.UTF-8' => 'Français',
+            'el_GR.UTF-8' => 'Ελληνικά',
+            'id_ID.UTF-8' => 'Indonesian',
+            'it_IT.UTF-8' => 'Italiano',
+            'ja_JP.UTF-8' => '日本語 (Japanese)',
+            'ko_KR.UTF-8' => '한국어 (Korean)',
+            'nl_NL.UTF-8' => 'Nederlands',
+            'pl_PL.UTF-8' => 'Polskie',
+            'pt_BR.UTF-8' => 'Português',
+            'ru_RU.UTF-8' => 'Русский',
+            'ro_RO.UTF-8' => 'Română',
+            'sk_SK.UTF-8' => 'Slovenčina',
+            'sv_SE.UTF-8' => 'Svenska',
+            'tr_TR.UTF-8' => 'Türkçe',
+            'vi_VN.UTF-8' => 'Tiếng Việt (Vietnamese)'
+        ];
+    }
+
+    /**
+     * Get valid locale codes
+     *
+     * @return array Array of valid locale codes
+     */
+    public function getValidLocales(): array
+    {
+        return array_keys($this->getLocales());
+    }
+
+    /**
+     * Detect browser locale from Accept-Language header
+     *
+     * Language detection is performed via the browser.
+     * Accept-Language returns a list of weighted values with a quality (or 'q') parameter.
+     * A better method would parse the list of preferred languages and match this with
+     * the languages supported by our platform.
+     *
+     * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
+     * @return string Detected locale code
+     */
+    public function detectBrowserLocale(): string
+    {
+        if (empty($_SERVER['HTTP_ACCEPT_LANGUAGE']) || strlen($_SERVER['HTTP_ACCEPT_LANGUAGE']) < 2) {
+            return self::DEFAULT_LOCALE;
+        }
+
+        $acceptLang = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
+        $lang = strtolower(substr($acceptLang, 0, 2));
+
+        if ($lang === 'zh' && strpos($acceptLang, 'zh-TW') === 0) {
+            return 'zh_TW.UTF-8';
+        }
+
+        switch ($lang) {
+            case 'de':
+                return 'de_DE.UTF-8';
+            case 'fr':
+                return 'fr_FR.UTF-8';
+            case 'it':
+                return 'it_IT.UTF-8';
+            case 'pt':
+                return 'pt_BR.UTF-8';
+            case 'sv':
+                return 'sv_SE.UTF-8';
+            case 'nl':
+                return 'nl_NL.UTF-8';
+            case 'zh':
+                return 'zh_CN.UTF-8';
+            case 'cs':
+                return 'cs_CZ.UTF-8';
+            case 'ru':
+                return 'ru_RU.UTF-8';
+            case 'es':
+                return 'es_MX.UTF-8';
+            case 'fi':
+                return 'fi_FI.UTF-8';
+            case 'da':
+                return 'da_DK.UTF-8';
+            case 'tr':
+                return 'tr_TR.UTF-8';
+            case 'id':
+                return 'id_ID.UTF-8';
+            case 'ko':
+                return 'ko_KR.UTF-8';
+            case 'ja':
+                return 'ja_JP.UTF-8';
+            case 'vi':
+                return 'vi_VN.UTF-8';
+            case 'el':
+                return 'el_GR.UTF-8';
+            case 'pl':
+                return 'pl_PL.UTF-8';
+            case 'sk':
+                return 'sk_SK.UTF-8';
+            default:
+                return self::DEFAULT_LOCALE;
+        }
+    }
+
+    /**
+     * Validate if a locale code is valid
+     *
+     * Uses $validLocales to mitigate OS Command Injection (CWE-78)
+     * @see Vulnerability Report for JVN #27202136
+     *
+     * @param string $locale Locale code to validate
+     * @return bool True if valid, false otherwise
+     */
+    public function isValidLocale(string $locale): bool
+    {
+        return in_array($locale, $this->getValidLocales(), true);
+    }
+
+    /**
+     * Set the current locale
+     *
+     * @param string $locale Locale code to set
+     * @return bool true if locale was set, false if invalid
+     */
+    public function setLocale(string $locale): bool
+    {
+        if (!$this->isValidLocale($locale)) {
+            return false;
+        }
+
+        $this->locale = $locale;
+        return true;
+    }
+
+    /**
+     * Get the current locale
+     *
+     * @return string Current locale code
+     */
+    public function getCurrentLocale(): string
+    {
+        return $this->locale;
+    }
+
+    /**
+     * Initialize locale
+     *
+     * @return void
+     */
+    public function initialize(): void
+    {
+        $validLocales = $this->getValidLocales();
+
+        // Set locale from POST, if provided and valid
+        if (!empty($_POST['locale']) && in_array($_POST['locale'], $validLocales, true)) {
+            $_SESSION['locale'] = $_POST['locale'];
+            $this->setLocaleCookie($_POST['locale']);
+        }
+
+        // Set locale from cookie or browser detection, if not already set in session
+        if (empty($_SESSION['locale'])) {
+            if (isset($_COOKIE['locale']) && in_array($_COOKIE['locale'], $validLocales, true)) {
+                $_SESSION['locale'] = $_COOKIE['locale'];
+            } else {
+                $_SESSION['locale'] = $this->detectBrowserLocale();
+                $this->setLocaleCookie($_SESSION['locale']);
+            }
+        }
+
+        // Enforce only valid locale values in session
+        if (!in_array($_SESSION['locale'], $validLocales, true)) {
+            $_SESSION['locale'] = self::DEFAULT_LOCALE;
+            $this->setLocaleCookie($_SESSION['locale']);
+        }
+
+        // Update internal state
+        $this->locale = $_SESSION['locale'];
+    }
+
+    /**
+     * Apply locale settings to the system
+     *
+     * Sets environment variables and configures gettext
+     *
+     * @return void
+     */
+    public function applyLocale(): void
+    {
+        putenv("LANG=" . escapeshellarg($this->locale));
+        setlocale(LC_ALL, $this->locale);
+
+        // Use global constants if defined, otherwise use defaults
+        $localeDomain = defined('LOCALE_DOMAIN') ? LOCALE_DOMAIN : 'messages';
+        $localeRoot = defined('LOCALE_ROOT') ? LOCALE_ROOT : 'locale';
+
+        bindtextdomain($localeDomain, $localeRoot);
+        bind_textdomain_codeset($localeDomain, 'UTF-8');
+        textdomain($localeDomain);
+    }
+
+    /**
+     * Set locale cookie
+     *
+     * @param string $locale Locale code to store in cookie
+     * @return void
+     */
+    private function setLocaleCookie(string $locale): void
+    {
+        setcookie('locale', $locale, time() + self::COOKIE_LIFETIME, '/', '', false, true);
+    }
+
+    /**
+     * Initialize and apply locale in one call
+     *
+     * @return void
+     */
+    public function initializeAndApply(): void
+    {
+        $this->initialize();
+        $this->applyLocale();
+    }
+}