diff --git a/system/Commands/Translation/LocalizationSync.php b/system/Commands/Translation/LocalizationSync.php
new file mode 100644
index 000000000000..b2614ab3ca2e
--- /dev/null
+++ b/system/Commands/Translation/LocalizationSync.php
@@ -0,0 +1,202 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Commands\Translation;
+
+use CodeIgniter\CLI\BaseCommand;
+use CodeIgniter\CLI\CLI;
+use CodeIgniter\Exceptions\LogicException;
+use Config\App;
+use ErrorException;
+use FilesystemIterator;
+use Locale;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use SplFileInfo;
+
+/**
+ * @see \CodeIgniter\Commands\Translation\LocalizationSyncTest
+ */
+class LocalizationSync extends BaseCommand
+{
+    protected $group       = 'Translation';
+    protected $name        = 'lang:sync';
+    protected $description = 'Synchronize translation files from one language to another.';
+    protected $usage       = 'lang:sync [options]';
+    protected $arguments   = [];
+    protected $options     = [
+        '--locale' => 'The original locale (en, ru, etc.).',
+        '--target' => 'Target locale (en, ru, etc.).',
+    ];
+    private string $languagePath;
+
+    public function run(array $params)
+    {
+        $optionTargetLocale = '';
+        $optionLocale       = $params['locale'] ?? Locale::getDefault();
+        $this->languagePath = APPPATH . 'Language';
+
+        if (isset($params['target']) && $params['target'] !== '') {
+            $optionTargetLocale = $params['target'];
+        }
+
+        if (! in_array($optionLocale, config(App::class)->supportedLocales, true)) {
+            CLI::error(
+                'Error: "' . $optionLocale . '" is not supported. Supported locales: '
+                . implode(', ', config(App::class)->supportedLocales)
+            );
+
+            return EXIT_USER_INPUT;
+        }
+
+        if ($optionTargetLocale === '') {
+            CLI::error(
+                'Error: "--target" is not configured. Supported locales: '
+                . implode(', ', config(App::class)->supportedLocales)
+            );
+
+            return EXIT_USER_INPUT;
+        }
+
+        if (! in_array($optionTargetLocale, config(App::class)->supportedLocales, true)) {
+            CLI::error(
+                'Error: "' . $optionTargetLocale . '" is not supported. Supported locales: '
+                . implode(', ', config(App::class)->supportedLocales)
+            );
+
+            return EXIT_USER_INPUT;
+        }
+
+        if ($optionTargetLocale === $optionLocale) {
+            CLI::error(
+                'Error: You cannot have the same values for "--target" and "--locale".'
+            );
+
+            return EXIT_USER_INPUT;
+        }
+
+        if (ENVIRONMENT === 'testing') {
+            $this->languagePath = SUPPORTPATH . 'Language';
+        }
+
+        if ($this->process($optionLocale, $optionTargetLocale) === EXIT_ERROR) {
+            return EXIT_ERROR;
+        }
+
+        CLI::write('All operations done!');
+
+        return EXIT_SUCCESS;
+    }
+
+    private function process(string $originalLocale, string $targetLocale): int
+    {
+        $originalLocaleDir = $this->languagePath . DIRECTORY_SEPARATOR . $originalLocale;
+        $targetLocaleDir   = $this->languagePath . DIRECTORY_SEPARATOR . $targetLocale;
+
+        if (! is_dir($originalLocaleDir)) {
+            CLI::error(
+                'Error: The "' . clean_path($originalLocaleDir) . '" directory was not found.'
+            );
+
+            return EXIT_ERROR;
+        }
+
+        // Unifying the error - mkdir() may cause an exception.
+        try {
+            if (! is_dir($targetLocaleDir) && ! mkdir($targetLocaleDir, 0775)) {
+                throw new ErrorException();
+            }
+        } catch (ErrorException $e) {
+            CLI::error(
+                'Error: The target directory "' . clean_path($targetLocaleDir) . '" cannot be accessed.'
+            );
+
+            return EXIT_ERROR;
+        }
+
+        $iterator = new RecursiveIteratorIterator(
+            new RecursiveDirectoryIterator(
+                $originalLocaleDir,
+                FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_FILEINFO | FilesystemIterator::SKIP_DOTS
+            )
+        );
+
+        /**
+         * @var array<non-empty-string, SplFileInfo> $files
+         */
+        $files = iterator_to_array($iterator, true);
+        ksort($files);
+
+        foreach ($files as $originalLanguageFile) {
+            if ($originalLanguageFile->getExtension() !== 'php') {
+                continue;
+            }
+
+            $targetLanguageFile = $targetLocaleDir . DIRECTORY_SEPARATOR . $originalLanguageFile->getFilename();
+
+            $targetLanguageKeys   = [];
+            $originalLanguageKeys = include $originalLanguageFile;
+
+            if (is_file($targetLanguageFile)) {
+                $targetLanguageKeys = include $targetLanguageFile;
+            }
+
+            $targetLanguageKeys = $this->mergeLanguageKeys($originalLanguageKeys, $targetLanguageKeys, $originalLanguageFile->getBasename('.php'));
+
+            $content = "<?php\n\nreturn " . var_export($targetLanguageKeys, true) . ";\n";
+            file_put_contents($targetLanguageFile, $content);
+        }
+
+        return EXIT_SUCCESS;
+    }
+
+    /**
+     * @param array<string, array<string,mixed>|string|null> $originalLanguageKeys
+     * @param array<string, array<string,mixed>|string|null> $targetLanguageKeys
+     *
+     * @return array<string, array<string,mixed>|string|null>
+     */
+    private function mergeLanguageKeys(array $originalLanguageKeys, array $targetLanguageKeys, string $prefix = ''): array
+    {
+        $mergedLanguageKeys = [];
+
+        foreach ($originalLanguageKeys as $key => $value) {
+            $placeholderValue = $prefix !== '' ? $prefix . '.' . $key : $key;
+
+            if (is_string($value)) {
+                // Keep the old value
+                // TODO: The value type may not match the original one
+                if (array_key_exists($key, $targetLanguageKeys)) {
+                    $mergedLanguageKeys[$key] = $targetLanguageKeys[$key];
+
+                    continue;
+                }
+
+                // Set new key with placeholder
+                $mergedLanguageKeys[$key] = $placeholderValue;
+            } elseif (is_array($value)) {
+                if (! array_key_exists($key, $targetLanguageKeys)) {
+                    $mergedLanguageKeys[$key] = $this->mergeLanguageKeys($value, [], $placeholderValue);
+
+                    continue;
+                }
+
+                $mergedLanguageKeys[$key] = $this->mergeLanguageKeys($value, $targetLanguageKeys[$key], $placeholderValue);
+            } else {
+                throw new LogicException('Value for the key "' . $placeholderValue . '" is of the wrong type. Only "array" or "string" is allowed.');
+            }
+        }
+
+        return $mergedLanguageKeys;
+    }
+}
diff --git a/tests/system/Commands/Translation/LocalizationSyncTest.php b/tests/system/Commands/Translation/LocalizationSyncTest.php
new file mode 100644
index 000000000000..88d7dc6f3bd6
--- /dev/null
+++ b/tests/system/Commands/Translation/LocalizationSyncTest.php
@@ -0,0 +1,275 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Commands\Translation;
+
+use CodeIgniter\Exceptions\LogicException;
+use CodeIgniter\Test\CIUnitTestCase;
+use CodeIgniter\Test\ReflectionHelper;
+use CodeIgniter\Test\StreamFilterTrait;
+use Config\App;
+use Locale;
+use PHPUnit\Framework\Attributes\Group;
+
+/**
+ * @internal
+ */
+#[Group('Others')]
+final class LocalizationSyncTest extends CIUnitTestCase
+{
+    use StreamFilterTrait;
+    use ReflectionHelper;
+
+    private static string $locale;
+    private static string $languageTestPath;
+
+    /**
+     * @var array<string, array<string,mixed>|string|null>
+     */
+    private array $expectedKeys = [
+        'title'  => 'Sync.title',
+        'status' => [
+            'error'    => 'Sync.status.error',
+            'done'     => 'Sync.status.done',
+            'critical' => 'Sync.status.critical',
+        ],
+        'description' => 'Sync.description',
+        'empty_array' => [],
+        'more'        => [
+            'nested' => [
+                'key' => 'Sync.more.nested.key',
+            ],
+        ],
+    ];
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        config(App::class)->supportedLocales = ['en', 'ru', 'de'];
+
+        self::$locale           = Locale::getDefault();
+        self::$languageTestPath = SUPPORTPATH . 'Language/';
+        $this->makeLanguageFiles();
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+
+        $this->clearGeneratedFiles();
+    }
+
+    public function testSyncDefaultLocale(): void
+    {
+        command('lang:sync --target de');
+
+        $langFile = self::$languageTestPath . 'de/Sync.php';
+
+        $this->assertFileExists($langFile);
+
+        $langKeys = include $langFile;
+
+        $this->assertIsArray($langKeys);
+        $this->assertSame($this->expectedKeys, $langKeys);
+    }
+
+    public function testSyncWithLocaleOption(): void
+    {
+        command('lang:sync --locale ru --target de');
+
+        $langFile = self::$languageTestPath . 'de/Sync.php';
+
+        $this->assertFileExists($langFile);
+
+        $langKeys = include $langFile;
+
+        $this->assertIsArray($langKeys);
+        $this->assertSame($this->expectedKeys, $langKeys);
+    }
+
+    public function testSyncWithExistTranslation(): void
+    {
+        // Save old values and add new keys from "en/Sync.php"
+        // Add value from the old file "de/Sync.php" to new
+        // Right sort as in "en/Sync.php"
+        $expectedLangKeys = [
+            'title'  => 'Default title (old)',
+            'status' => [
+                'error'    => 'Error! (old)',
+                'done'     => 'Sync.status.done',
+                'critical' => 'Critical! (old)',
+            ],
+            'description' => 'Sync.description',
+            'empty_array' => [],
+            'more'        => [
+                'nested' => [
+                    'key' => 'More nested key... (old)',
+                ],
+            ],
+        ];
+
+        $lang = <<<'TEXT_WRAP'
+            <?php
+
+            return [
+                'status' => [
+                    'critical' => 'Critical! (old)',
+                    'error'    => 'Error! (old)',
+                ],
+                'skip'        => 'skip this value',
+                'title'  => 'Default title (old)',
+                'more'        => [
+                    'nested' => [
+                        'key' => 'More nested key... (old)',
+                    ],
+                ],
+                'empty_array' => [],
+            ];
+            TEXT_WRAP;
+
+        $langFile = self::$languageTestPath . 'de/Sync.php';
+
+        mkdir(self::$languageTestPath . 'de', 0755);
+        file_put_contents($langFile, $lang);
+
+        command('lang:sync --target de');
+
+        $this->assertFileExists($langFile);
+
+        $langKeys = include $langFile;
+
+        $this->assertIsArray($langKeys);
+        $this->assertSame($expectedLangKeys, $langKeys);
+    }
+
+    public function testSyncWithIncorrectLocaleOption(): void
+    {
+        command('lang:sync --locale test_locale_incorrect --target de');
+
+        $this->assertStringContainsString('is not supported', $this->getStreamFilterBuffer());
+    }
+
+    public function testSyncWithNullableOriginalLangValue(): void
+    {
+        $langWithNullValue = <<<'TEXT_WRAP'
+            <?php
+
+            return [
+                'nullable' => null,
+            ];
+            TEXT_WRAP;
+
+        file_put_contents(self::$languageTestPath . self::$locale . '/SyncInvalid.php', $langWithNullValue);
+        ob_get_flush();
+
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessageMatches('/Only "array" or "string" is allowed/');
+
+        command('lang:sync --target de');
+    }
+
+    public function testSyncWithIntegerOriginalLangValue(): void
+    {
+        $this->resetStreamFilterBuffer();
+
+        $langWithIntegerValue = <<<'TEXT_WRAP'
+            <?php
+
+            return [
+                'integer' => 1000,
+            ];
+            TEXT_WRAP;
+
+        file_put_contents(self::$languageTestPath . self::$locale . '/SyncInvalid.php', $langWithIntegerValue);
+        ob_get_flush();
+
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessageMatches('/Only "array" or "string" is allowed/');
+
+        command('lang:sync --target de');
+    }
+
+    public function testSyncWithIncorrectTargetOption(): void
+    {
+        command('lang:sync --locale en --target test_locale_incorrect');
+
+        $this->assertStringContainsString('is not supported', $this->getStreamFilterBuffer());
+    }
+
+    public function testProcessWithInvalidOption(): void
+    {
+        $langPath = SUPPORTPATH . 'Language';
+        $command  = new LocalizationSync(service('logger'), service('commands'));
+        $this->setPrivateProperty($command, 'languagePath', $langPath);
+        $runner = $this->getPrivateMethodInvoker($command, 'process');
+
+        $status = $runner('de', 'jp');
+
+        $this->assertSame(EXIT_ERROR, $status);
+        $this->assertStringContainsString('Error: The "ROOTPATH/tests/_support/Language/de" directory was not found.', $this->getStreamFilterBuffer());
+
+        chmod($langPath, 0544);
+        $status = $runner('en', 'jp');
+        chmod($langPath, 0775);
+
+        $this->assertSame(EXIT_ERROR, $status);
+        $this->assertStringContainsString('Error: The target directory "ROOTPATH/tests/_support/Language/jp" cannot be accessed.', $this->getStreamFilterBuffer());
+    }
+
+    private function makeLanguageFiles(): void
+    {
+        $lang = <<<'TEXT_WRAP'
+            <?php
+
+            return [
+                'title'  => 'Default title',
+                'status' => [
+                    'error'    => 'Error!',
+                    'done'     => 'Done!',
+                    'critical' => 'Critical!',
+                ],
+                'description' => '',
+                'empty_array' => [],
+                'more'        => [
+                    'nested' => [
+                        'key' => 'More nested key...',
+                    ],
+                ],
+            ];
+            TEXT_WRAP;
+
+        file_put_contents(self::$languageTestPath . self::$locale . '/Sync.php', $lang);
+        file_put_contents(self::$languageTestPath . 'ru/Sync.php', $lang);
+    }
+
+    private function clearGeneratedFiles(): void
+    {
+        $files = [
+            self::$languageTestPath . self::$locale . '/Sync.php',
+            self::$languageTestPath . self::$locale . '/SyncInvalid.php',
+            self::$languageTestPath . 'ru/Sync.php',
+        ];
+
+        foreach ($files as $file) {
+            if (is_file($file)) {
+                unlink($file);
+            }
+        }
+
+        if (is_dir(self::$languageTestPath . 'de')) {
+            delete_files(self::$languageTestPath . 'de');
+            rmdir(self::$languageTestPath . 'de');
+        }
+    }
+}
diff --git a/user_guide_src/source/changelogs/v4.6.0.rst b/user_guide_src/source/changelogs/v4.6.0.rst
index d6429bf236e8..c31b628ccf55 100644
--- a/user_guide_src/source/changelogs/v4.6.0.rst
+++ b/user_guide_src/source/changelogs/v4.6.0.rst
@@ -234,6 +234,7 @@ Commands
 - The ``spark routes`` and ``spark filter:check`` commands now display filter
   arguments.
 - The ``spark filter:check`` command now displays filter classnames.
+- The ``spark lang:sync`` command to synchronize translation files. See :ref:`sync-translations-command`
 
 Routing
 =======
diff --git a/user_guide_src/source/outgoing/localization.rst b/user_guide_src/source/outgoing/localization.rst
index c5fba00adbc5..dfbc6d3130ac 100644
--- a/user_guide_src/source/outgoing/localization.rst
+++ b/user_guide_src/source/outgoing/localization.rst
@@ -366,3 +366,29 @@ Detailed information can be found by running the command:
 .. code-block:: console
 
     php spark lang:find --help
+
+.. _sync-translations-command:
+
+Synchronization Translation Files via Command
+---------------------------------------------
+
+.. versionadded:: 4.6.0
+
+You may need to create files for another language when you've finished translating for the current language. You can use the spark ``lang:find`` command to help with this. However, it might not detect all translations, particularly those with dynamically set parameters like ``lang('App.status.' . $key, ['payload' => 'John'], 'en')``.
+
+To ensure no translations are missed, it's best to copy the completed language files and translate them manually. This approach preserves any unique keys the command might have overlooked.
+
+All you need to do is execute:
+
+.. code-block:: console
+
+    // Specify the locale for new/updated translations
+    php spark lang:sync --target ru
+
+    // or set the original locale
+    php spark lang:sync --locale en --target ru
+
+As a result, you will receive files with the translation keys.
+If there were duplicate keys in the target locale, they are saved.
+
+.. warning:: Non-matching keys in new translations are deleted!