diff --git a/system/Commands/Translation/LocalizationFinder.php b/system/Commands/Translation/LocalizationFinder.php
new file mode 100644
index 000000000000..e5147093d2dc
--- /dev/null
+++ b/system/Commands/Translation/LocalizationFinder.php
@@ -0,0 +1,357 @@
+<?php
+
+/**
+ * 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\Commands\Translation\LocalizationFinder\ArrayHelper;
+use Config\App;
+use Locale;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use SplFileInfo;
+
+/**
+ * @see \CodeIgniter\Commands\Translation\LocalizationFinderTest
+ */
+class LocalizationFinder extends BaseCommand
+{
+    protected $group       = 'Translation';
+    protected $name        = 'lang:find';
+    protected $description = 'Find and save available phrases to translate.';
+    protected $usage       = 'lang:find [options]';
+    protected $arguments   = [];
+    protected $options     = [
+        '--locale'   => 'Specify locale (en, ru, etc.) to save files.',
+        '--dir'      => 'Directory to search for translations relative to APPPATH.',
+        '--show-new' => 'Show only new translations in table. Does not write to files.',
+        '--verbose'  => 'Output detailed information.',
+    ];
+
+    /**
+     * Flag for output detailed information
+     */
+    private bool $verbose = false;
+
+    /**
+     * Flag for showing only translations, without saving
+     */
+    private bool $showNew = false;
+
+    private string $languagePath;
+
+    public function run(array $params)
+    {
+        $this->verbose      = array_key_exists('verbose', $params);
+        $this->showNew      = array_key_exists('show-new', $params);
+        $optionLocale       = $params['locale'] ?? null;
+        $optionDir          = $params['dir'] ?? null;
+        $currentLocale      = Locale::getDefault();
+        $currentDir         = APPPATH;
+        $this->languagePath = $currentDir . 'Language';
+
+        if (ENVIRONMENT === 'testing') {
+            $currentDir         = SUPPORTPATH . 'Services' . DIRECTORY_SEPARATOR;
+            $this->languagePath = SUPPORTPATH . 'Language';
+        }
+
+        if (is_string($optionLocale)) {
+            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;
+            }
+
+            $currentLocale = $optionLocale;
+        }
+
+        if (is_string($optionDir)) {
+            $tempCurrentDir = realpath($currentDir . $optionDir);
+
+            if (false === $tempCurrentDir) {
+                CLI::error('Error: Directory must be located in "' . $currentDir . '"');
+
+                return EXIT_USER_INPUT;
+            }
+
+            if ($this->isSubDirectory($tempCurrentDir, $this->languagePath)) {
+                CLI::error('Error: Directory "' . $this->languagePath . '" restricted to scan.');
+
+                return EXIT_USER_INPUT;
+            }
+
+            $currentDir = $tempCurrentDir;
+        }
+
+        $this->process($currentDir, $currentLocale);
+
+        CLI::write('All operations done!');
+
+        return EXIT_SUCCESS;
+    }
+
+    private function process(string $currentDir, string $currentLocale): void
+    {
+        $tableRows    = [];
+        $countNewKeys = 0;
+
+        $iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($currentDir));
+        $files    = iterator_to_array($iterator, true);
+        ksort($files);
+
+        [$foundLanguageKeys, $countFiles] = $this->findLanguageKeysInFiles($files);
+        ksort($foundLanguageKeys);
+
+        $languageDiff        = [];
+        $languageFoundGroups = array_unique(array_keys($foundLanguageKeys));
+
+        foreach ($languageFoundGroups as $langFileName) {
+            $languageStoredKeys = [];
+            $languageFilePath   = $this->languagePath . DIRECTORY_SEPARATOR . $currentLocale . DIRECTORY_SEPARATOR . $langFileName . '.php';
+
+            if (is_file($languageFilePath)) {
+                // Load old localization
+                $languageStoredKeys = require $languageFilePath;
+            }
+
+            $languageDiff = ArrayHelper::recursiveDiff($foundLanguageKeys[$langFileName], $languageStoredKeys);
+            $countNewKeys += ArrayHelper::recursiveCount($languageDiff);
+
+            if ($this->showNew) {
+                $tableRows = array_merge($this->arrayToTableRows($langFileName, $languageDiff), $tableRows);
+            } else {
+                $newLanguageKeys = array_replace_recursive($foundLanguageKeys[$langFileName], $languageStoredKeys);
+
+                if ($languageDiff !== []) {
+                    if (false === file_put_contents($languageFilePath, $this->templateFile($newLanguageKeys))) {
+                        $this->writeIsVerbose('Lang file ' . $langFileName . ' (error write).', 'red');
+                    } else {
+                        $this->writeIsVerbose('Lang file "' . $langFileName . '" successful updated!', 'green');
+                    }
+                }
+            }
+        }
+
+        if ($this->showNew && $tableRows !== []) {
+            sort($tableRows);
+            CLI::table($tableRows, ['File', 'Key']);
+        }
+
+        if (! $this->showNew && $countNewKeys > 0) {
+            CLI::write('Note: You need to run your linting tool to fix coding standards issues.', 'white', 'red');
+        }
+
+        $this->writeIsVerbose('Files found: ' . $countFiles);
+        $this->writeIsVerbose('New translates found: ' . $countNewKeys);
+    }
+
+    /**
+     * @param SplFileInfo|string $file
+     */
+    private function findTranslationsInFile($file): array
+    {
+        $foundLanguageKeys = [];
+
+        if (is_string($file) && is_file($file)) {
+            $file = new SplFileInfo($file);
+        }
+
+        $fileContent = file_get_contents($file->getRealPath());
+        preg_match_all('/lang\(\'([._a-z0-9\-]+)\'\)/ui', $fileContent, $matches);
+
+        if ($matches[1] === []) {
+            return [];
+        }
+
+        foreach ($matches[1] as $phraseKey) {
+            $phraseKeys = explode('.', $phraseKey);
+
+            // Language key not have Filename or Lang key
+            if (count($phraseKeys) < 2) {
+                continue;
+            }
+
+            $languageFileName   = array_shift($phraseKeys);
+            $isEmptyNestedArray = ($languageFileName !== '' && $phraseKeys[0] === '')
+                || ($languageFileName === '' && $phraseKeys[0] !== '')
+                || ($languageFileName === '' && $phraseKeys[0] === '');
+
+            if ($isEmptyNestedArray) {
+                continue;
+            }
+
+            if (count($phraseKeys) === 1) {
+                $foundLanguageKeys[$languageFileName][$phraseKeys[0]] = $phraseKey;
+            } else {
+                $childKeys = $this->buildMultiArray($phraseKeys, $phraseKey);
+
+                $foundLanguageKeys[$languageFileName] = array_replace_recursive($foundLanguageKeys[$languageFileName] ?? [], $childKeys);
+            }
+        }
+
+        return $foundLanguageKeys;
+    }
+
+    private function isIgnoredFile(SplFileInfo $file): bool
+    {
+        if ($file->isDir() || $this->isSubDirectory($file->getRealPath(), $this->languagePath)) {
+            return true;
+        }
+
+        return $file->getExtension() !== 'php';
+    }
+
+    private function templateFile(array $language = []): string
+    {
+        if ($language !== []) {
+            $languageArrayString = var_export($language, true);
+
+            $code = <<<PHP
+                <?php
+
+                return {$languageArrayString};
+
+                PHP;
+
+            return $this->replaceArraySyntax($code);
+        }
+
+        return <<<'PHP'
+            <?php
+
+            return [];
+
+            PHP;
+    }
+
+    private function replaceArraySyntax(string $code): string
+    {
+        $tokens    = token_get_all($code);
+        $newTokens = $tokens;
+
+        foreach ($tokens as $i => $token) {
+            if (is_array($token)) {
+                [$tokenId, $tokenValue] = $token;
+
+                // Replace "array ("
+                if (
+                    $tokenId === T_ARRAY
+                    && $tokens[$i + 1][0] === T_WHITESPACE
+                    && $tokens[$i + 2] === '('
+                ) {
+                    $newTokens[$i][1]     = '[';
+                    $newTokens[$i + 1][1] = '';
+                    $newTokens[$i + 2]    = '';
+                }
+
+                // Replace indent
+                if ($tokenId === T_WHITESPACE && preg_match('/\n([ ]+)/u', $tokenValue, $matches)) {
+                    $newTokens[$i][1] = "\n{$matches[1]}{$matches[1]}";
+                }
+            } // Replace ")"
+            elseif ($token === ')') {
+                $newTokens[$i] = ']';
+            }
+        }
+
+        $output = '';
+
+        foreach ($newTokens as $token) {
+            $output .= $token[1] ?? $token;
+        }
+
+        return $output;
+    }
+
+    /**
+     * Create multidimensional array from another keys
+     */
+    private function buildMultiArray(array $fromKeys, string $lastArrayValue = ''): array
+    {
+        $newArray  = [];
+        $lastIndex = array_pop($fromKeys);
+        $current   = &$newArray;
+
+        foreach ($fromKeys as $value) {
+            $current[$value] = [];
+            $current         = &$current[$value];
+        }
+
+        $current[$lastIndex] = $lastArrayValue;
+
+        return $newArray;
+    }
+
+    /**
+     * Convert multi arrays to specific CLI table rows (flat array)
+     */
+    private function arrayToTableRows(string $langFileName, array $array): array
+    {
+        $rows = [];
+
+        foreach ($array as $value) {
+            if (is_array($value)) {
+                $rows = array_merge($rows, $this->arrayToTableRows($langFileName, $value));
+
+                continue;
+            }
+
+            if (is_string($value)) {
+                $rows[] = [$langFileName, $value];
+            }
+        }
+
+        return $rows;
+    }
+
+    /**
+     * Show details in the console if the flag is set
+     */
+    private function writeIsVerbose(string $text = '', ?string $foreground = null, ?string $background = null): void
+    {
+        if ($this->verbose) {
+            CLI::write($text, $foreground, $background);
+        }
+    }
+
+    private function isSubDirectory(string $directory, string $rootDirectory): bool
+    {
+        return 0 === strncmp($directory, $rootDirectory, strlen($directory));
+    }
+
+    /**
+     * @param SplFileInfo[] $files
+     *
+     * @return array<int, array|int>
+     * @phpstan-return list{0: array<string, array<string, string>>, 1: int}
+     */
+    private function findLanguageKeysInFiles(array $files): array
+    {
+        $foundLanguageKeys = [];
+        $countFiles        = 0;
+
+        foreach ($files as $file) {
+            if ($this->isIgnoredFile($file)) {
+                continue;
+            }
+
+            $this->writeIsVerbose('File found: ' . mb_substr($file->getRealPath(), mb_strlen(APPPATH)));
+            $countFiles++;
+            $foundLanguageKeys = array_replace_recursive($this->findTranslationsInFile($file), $foundLanguageKeys);
+        }
+
+        return [$foundLanguageKeys, $countFiles];
+    }
+}
diff --git a/system/Commands/Translation/LocalizationFinder/ArrayHelper.php b/system/Commands/Translation/LocalizationFinder/ArrayHelper.php
new file mode 100644
index 000000000000..d747127c3a42
--- /dev/null
+++ b/system/Commands/Translation/LocalizationFinder/ArrayHelper.php
@@ -0,0 +1,72 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Commands\Translation\LocalizationFinder;
+
+class ArrayHelper
+{
+    /**
+     * Compare recursively two associative arrays and return difference as new array.
+     * Returns keys that exist in `$original` but not in `$compareWith`.
+     */
+    public static function recursiveDiff(array $original, array $compareWith): array
+    {
+        $difference = [];
+
+        if ($original === []) {
+            return [];
+        }
+
+        if ($compareWith === []) {
+            return $original;
+        }
+
+        foreach ($original as $originalKey => $originalValue) {
+            if ($originalValue === []) {
+                continue;
+            }
+
+            if (is_array($originalValue)) {
+                $diffArrays = [];
+
+                if (isset($compareWith[$originalKey]) && is_array($compareWith[$originalKey])) {
+                    $diffArrays = self::recursiveDiff($originalValue, $compareWith[$originalKey]);
+                } else {
+                    $difference[$originalKey] = $originalValue;
+                }
+
+                if ($diffArrays !== []) {
+                    $difference[$originalKey] = $diffArrays;
+                }
+            } elseif (is_string($originalValue) && ! array_key_exists($originalKey, $compareWith)) {
+                $difference[$originalKey] = $originalValue;
+            }
+        }
+
+        return $difference;
+    }
+
+    /**
+     * Recursively count all keys.
+     */
+    public static function recursiveCount(array $array, int $counter = 0): int
+    {
+        foreach ($array as $value) {
+            if (is_array($value)) {
+                $counter = self::recursiveCount($value, $counter);
+            }
+
+            $counter++;
+        }
+
+        return $counter;
+    }
+}
diff --git a/tests/_support/Services/Translation/TranslationNested/TranslationFour.php b/tests/_support/Services/Translation/TranslationNested/TranslationFour.php
new file mode 100644
index 000000000000..545e821bb049
--- /dev/null
+++ b/tests/_support/Services/Translation/TranslationNested/TranslationFour.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * 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 Tests\Support\Services\Translation\Nested;
+
+class TranslationFour
+{
+    public function list()
+    {
+        $translationOne1 = lang('TranslationOne.title');
+        $translationOne5 = lang('TranslationOne.last_operation_success');
+
+        $translationThree1 = lang('TranslationThree.alerts.created');
+        $translationThree2 = lang('TranslationThree.alerts.failed_insert');
+
+        $translationThree5 = lang('TranslationThree.formFields.new.name');
+        $translationThree7 = lang('TranslationThree.formFields.new.short_tag');
+
+        $translationFour1 = lang('Translation-Four.dashed.key-with-dash');
+        $translationFour2 = lang('Translation-Four.dashed.key-with-dash-two');
+    }
+}
diff --git a/tests/_support/Services/Translation/TranslationOne.php b/tests/_support/Services/Translation/TranslationOne.php
new file mode 100644
index 000000000000..bf6b0e1e31c1
--- /dev/null
+++ b/tests/_support/Services/Translation/TranslationOne.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * 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 Tests\Support\Services\Translation;
+
+class TranslationOne
+{
+    public function list()
+    {
+        $translationOne1 = lang('TranslationOne.title');
+        $translationOne2 = lang('TranslationOne.DESCRIPTION');
+        $translationOne3 = lang('TranslationOne.metaTags');
+        $translationOne4 = lang('TranslationOne.Copyright');
+        $translationOne5 = lang('TranslationOne.last_operation_success');
+
+        $translationThree1 = lang('TranslationThree.alerts.created');
+        $translationThree2 = lang('TranslationThree.alerts.failed_insert');
+        $translationThree3 = lang('TranslationThree.alerts.Updated');
+        $translationThree4 = lang('TranslationThree.alerts.DELETED');
+
+        $translationThree5  = lang('TranslationThree.formFields.new.name');
+        $translationThree6  = lang('TranslationThree.formFields.new.TEXT');
+        $translationThree7  = lang('TranslationThree.formFields.new.short_tag');
+        $translationThree8  = lang('TranslationThree.formFields.edit.name');
+        $translationThree9  = lang('TranslationThree.formFields.edit.TEXT');
+        $translationThree10 = lang('TranslationThree.formFields.edit.short_tag');
+    }
+}
diff --git a/tests/_support/Services/Translation/TranslationThree.php b/tests/_support/Services/Translation/TranslationThree.php
new file mode 100644
index 000000000000..d9da9ba67c75
--- /dev/null
+++ b/tests/_support/Services/Translation/TranslationThree.php
@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * 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 Tests\Support\Services\Translation;
+
+class TranslationThree
+{
+    public function list()
+    {
+        $translationOne1 = lang('TranslationOne.title');
+        $translationOne2 = lang('TranslationOne.DESCRIPTION');
+        $translationOne6 = lang('TranslationOne.subTitle');
+        $translationOne7 = lang('TranslationOne.overflow_style');
+
+        $translationThree1 = lang('TranslationThree.alerts.created');
+        $translationThree2 = lang('TranslationThree.alerts.failed_insert');
+
+        $translationThree5 = lang('TranslationThree.formFields.new.name');
+        $translationThree6 = lang('TranslationThree.formFields.new.TEXT');
+        $translationThree7 = lang('TranslationThree.formFields.new.short_tag');
+
+        $translationThree11 = lang('TranslationThree.alerts.CANCELED');
+        $translationThree12 = lang('TranslationThree.alerts.missing_keys');
+
+        $translationThree13 = lang('TranslationThree.formErrors.edit.empty_name');
+        $translationThree14 = lang('TranslationThree.formErrors.edit.INVALID_TEXT');
+        $translationThree15 = lang('TranslationThree.formErrors.edit.missing_short_tag');
+    }
+}
diff --git a/tests/_support/Services/Translation/TranslationTwo.php b/tests/_support/Services/Translation/TranslationTwo.php
new file mode 100644
index 000000000000..71e5e663b27e
--- /dev/null
+++ b/tests/_support/Services/Translation/TranslationTwo.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * 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 Tests\Support\Services\Translation;
+
+class TranslationTwo
+{
+    public function list()
+    {
+        $langKey = 'TranslationTwo.error_key';
+
+        // Error language keys
+        $translationError1 = lang('TranslationTwo');
+        $translationError2 = lang(' ');
+        $translationError3 = lang('');
+        $translationError4 = lang('.invalid_key');
+        $translationError5 = lang('TranslationTwo.');
+        $translationError6 = lang('TranslationTwo...');
+        $translationError7 = lang('..invalid_nested_key..');
+
+        // Empty in comments lang('') lang(' ')
+    }
+}
diff --git a/tests/system/Commands/Translation/LocalizationFinder/ArrayHelperTest.php b/tests/system/Commands/Translation/LocalizationFinder/ArrayHelperTest.php
new file mode 100644
index 000000000000..499d092521fe
--- /dev/null
+++ b/tests/system/Commands/Translation/LocalizationFinder/ArrayHelperTest.php
@@ -0,0 +1,238 @@
+<?php
+
+/**
+ * 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\TranslationLocalizationFinder;
+
+use CodeIgniter\Commands\Translation\LocalizationFinder\ArrayHelper;
+use CodeIgniter\Test\CIUnitTestCase;
+
+/**
+ * @group Others
+ *
+ * @internal
+ */
+final class ArrayHelperTest extends CIUnitTestCase
+{
+    private array $compareWith;
+
+    protected function setUp(): void
+    {
+        $this->compareWith = [
+            'a' => [
+                'b' => [
+                    'c' => [
+                        'd' => 'value1',
+                    ],
+                ],
+                'e' => 'value2',
+                'f' => [
+                    'g' => 'value3',
+                    'h' => 'value4',
+                    'i' => [
+                        'j' => 'value5',
+                    ],
+                ],
+                'k' => null,
+                'l' => [],
+                'm' => '',
+            ],
+        ];
+    }
+
+    public function testRecursiveDiffCopy(): void
+    {
+        $this->assertSame([], ArrayHelper::recursiveDiff($this->compareWith, $this->compareWith));
+    }
+
+    public function testRecursiveDiffShuffleCopy(): void
+    {
+        $original = [
+            'a' => [
+                'l' => [],
+                'k' => null,
+                'e' => 'value2',
+                'f' => [
+                    'i' => [
+                        'j' => 'value5',
+                    ],
+                    'h' => 'value4',
+                    'g' => 'value3',
+                ],
+                'm' => '',
+                'b' => [
+                    'c' => [
+                        'd' => 'value1',
+                    ],
+                ],
+            ],
+        ];
+
+        $this->assertSame([], ArrayHelper::recursiveDiff($original, $this->compareWith));
+    }
+
+    public function testRecursiveDiffCopyWithAnotherValues(): void
+    {
+        $original = [
+            'a' => [
+                'b' => [
+                    'c' => [
+                        'd' => 'value1_1',
+                    ],
+                ],
+                'e' => 'value2_2',
+                'f' => [
+                    'g' => 'value3_3',
+                    'h' => 'value4_4',
+                    'i' => [
+                        'j' => 'value5_5',
+                    ],
+                ],
+                'k' => [],
+                'l' => null,
+                'm' => 'value6_6',
+            ],
+        ];
+
+        $this->assertSame([], ArrayHelper::recursiveDiff($original, $this->compareWith));
+    }
+
+    public function testRecursiveDiffEmptyCompare(): void
+    {
+        $this->assertSame($this->compareWith, ArrayHelper::recursiveDiff($this->compareWith, []));
+    }
+
+    public function testRecursiveDiffEmptyOriginal(): void
+    {
+        $this->assertSame([], ArrayHelper::recursiveDiff([], $this->compareWith));
+    }
+
+    public function testRecursiveDiffCompletelyDifferent(): void
+    {
+        $original = [
+            'new_a' => [
+                'new_b' => [
+                    'new_c' => [
+                        'new_d' => 'value1_1',
+                    ],
+                ],
+                'new_e' => 'value2_2',
+                'new_f' => [
+                    'new_g' => 'value3_3',
+                    'new_h' => 'value4_4',
+                    'new_i' => [
+                        'new_j' => 'value5_5',
+                    ],
+                ],
+                'new_k' => [],
+                'new_l' => null,
+                'new_m' => '',
+            ],
+        ];
+
+        $this->assertSame($original, ArrayHelper::recursiveDiff($original, $this->compareWith));
+    }
+
+    public function testRecursiveDiffPartlyDifferent(): void
+    {
+        $original = [
+            'a' => [
+                'b' => [
+                    'new_c' => [
+                        'd' => 'value1',
+                    ],
+                ],
+                'e' => 'value2',
+                'f' => [
+                    'g'     => 'value3',
+                    'new_h' => 'value4',
+                    'i'     => [
+                        'new_j' => 'value5',
+                    ],
+                ],
+                'k'     => null,
+                'new_l' => [],
+                'm'     => [
+                    'new_n' => '',
+                ],
+            ],
+        ];
+
+        $diff = [
+            'a' => [
+                'b' => [
+                    'new_c' => [
+                        'd' => 'value1',
+                    ],
+                ],
+                'f' => [
+                    'new_h' => 'value4',
+                    'i'     => [
+                        'new_j' => 'value5',
+                    ],
+                ],
+                'm' => [
+                    'new_n' => '',
+                ],
+            ],
+        ];
+
+        $this->assertSame($diff, ArrayHelper::recursiveDiff($original, $this->compareWith));
+    }
+
+    public function testRecursiveCountSimple(): void
+    {
+        $array = [
+            'a' => 'value1',
+            'b' => 'value2',
+            'c' => 'value3',
+        ];
+
+        $this->assertSame(3, ArrayHelper::recursiveCount($array));
+    }
+
+    public function testRecursiveCountNested(): void
+    {
+        $array = [
+            'a' => 'value1',
+            'b' => [
+                'c' => 'value2',
+            ],
+            'd' => 'value3',
+            'e' => [
+                'f' => [
+                    'g' => 'value4',
+                    'h' => [
+                        'i' => 'value5',
+                    ],
+                ],
+            ],
+            'j' => [],
+            'k' => null,
+        ];
+
+        $this->assertSame(11, ArrayHelper::recursiveCount($array));
+    }
+
+    public function testRecursiveCountEqualEmpty(): void
+    {
+        $array = [
+            'root' => [
+                'a' => [],
+                'b' => false,
+                'c' => null,
+                'd' => '',
+                'e' => 0,
+            ],
+        ];
+
+        $this->assertSame(6, ArrayHelper::recursiveCount($array));
+    }
+}
diff --git a/tests/system/Commands/Translation/LocalizationFinderTest.php b/tests/system/Commands/Translation/LocalizationFinderTest.php
new file mode 100644
index 000000000000..f5cc38ec7b2f
--- /dev/null
+++ b/tests/system/Commands/Translation/LocalizationFinderTest.php
@@ -0,0 +1,234 @@
+<?php
+
+/**
+ * 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\Test\CIUnitTestCase;
+use CodeIgniter\Test\StreamFilterTrait;
+use Config\App;
+use Config\Services;
+use Locale;
+
+/**
+ * @group Others
+ *
+ * @internal
+ */
+final class LocalizationFinderTest extends CIUnitTestCase
+{
+    use StreamFilterTrait;
+
+    private static string $locale;
+    private static string $languageTestPath;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        self::$locale           = Locale::getDefault();
+        self::$languageTestPath = SUPPORTPATH . 'Language' . DIRECTORY_SEPARATOR;
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+        $this->clearGeneratedFiles();
+    }
+
+    public function testUpdateDefaultLocale(): void
+    {
+        $this->makeLocaleDirectory();
+
+        command('lang:find --dir Translation');
+
+        $this->assertTranslationsExistAndHaveTranslatedKeys();
+    }
+
+    public function testUpdateWithLocaleOption(): void
+    {
+        self::$locale = config(App::class)->supportedLocales[0];
+        $this->makeLocaleDirectory();
+
+        command('lang:find --dir Translation --locale ' . self::$locale);
+
+        $this->assertTranslationsExistAndHaveTranslatedKeys();
+    }
+
+    public function testUpdateWithIncorrectLocaleOption(): void
+    {
+        self::$locale = 'test_locale_incorrect';
+        $this->makeLocaleDirectory();
+
+        $status = Services::commands()->run('lang:find', [
+            'dir'    => 'Translation',
+            'locale' => self::$locale,
+        ]);
+
+        $this->assertSame(EXIT_USER_INPUT, $status);
+    }
+
+    public function testUpdateWithEmptyDirOption(): void
+    {
+        $this->makeLocaleDirectory();
+
+        command('lang:find');
+
+        $this->assertTranslationsExistAndHaveTranslatedKeys();
+    }
+
+    public function testUpdateWithIncorrectDirOption(): void
+    {
+        $this->makeLocaleDirectory();
+
+        $status = Services::commands()->run('lang:find', [
+            'dir' => 'Translation/NotExistFolder',
+        ]);
+
+        $this->assertSame(EXIT_USER_INPUT, $status);
+    }
+
+    public function testShowNewTranslation(): void
+    {
+        $this->makeLocaleDirectory();
+
+        command('lang:find --dir Translation --show-new');
+
+        $this->assertStringContainsString($this->getActualTableWithNewKeys(), $this->getStreamFilterBuffer());
+    }
+
+    private function getActualTranslationOneKeys(): array
+    {
+        return [
+            'title'                  => 'TranslationOne.title',
+            'DESCRIPTION'            => 'TranslationOne.DESCRIPTION',
+            'subTitle'               => 'TranslationOne.subTitle',
+            'overflow_style'         => 'TranslationOne.overflow_style',
+            'metaTags'               => 'TranslationOne.metaTags',
+            'Copyright'              => 'TranslationOne.Copyright',
+            'last_operation_success' => 'TranslationOne.last_operation_success',
+        ];
+    }
+
+    private function getActualTranslationThreeKeys(): array
+    {
+        return [
+            'alerts' => [
+                'created'       => 'TranslationThree.alerts.created',
+                'failed_insert' => 'TranslationThree.alerts.failed_insert',
+                'CANCELED'      => 'TranslationThree.alerts.CANCELED',
+                'missing_keys'  => 'TranslationThree.alerts.missing_keys',
+                'Updated'       => 'TranslationThree.alerts.Updated',
+                'DELETED'       => 'TranslationThree.alerts.DELETED',
+            ],
+            'formFields' => [
+                'new' => [
+                    'name'      => 'TranslationThree.formFields.new.name',
+                    'TEXT'      => 'TranslationThree.formFields.new.TEXT',
+                    'short_tag' => 'TranslationThree.formFields.new.short_tag',
+                ],
+                'edit' => [
+                    'name'      => 'TranslationThree.formFields.edit.name',
+                    'TEXT'      => 'TranslationThree.formFields.edit.TEXT',
+                    'short_tag' => 'TranslationThree.formFields.edit.short_tag',
+                ],
+            ],
+            'formErrors' => [
+                'edit' => [
+                    'empty_name'        => 'TranslationThree.formErrors.edit.empty_name',
+                    'INVALID_TEXT'      => 'TranslationThree.formErrors.edit.INVALID_TEXT',
+                    'missing_short_tag' => 'TranslationThree.formErrors.edit.missing_short_tag',
+                ],
+            ],
+        ];
+    }
+
+    private function getActualTranslationFourKeys(): array
+    {
+        return [
+            'dashed' => [
+                'key-with-dash'     => 'Translation-Four.dashed.key-with-dash',
+                'key-with-dash-two' => 'Translation-Four.dashed.key-with-dash-two',
+            ],
+        ];
+    }
+
+    private function getActualTableWithNewKeys(): string
+    {
+        return <<<'TEXT_WRAP'
+            +------------------+----------------------------------------------------+
+            | File             | Key                                                |
+            +------------------+----------------------------------------------------+
+            | Translation-Four | Translation-Four.dashed.key-with-dash              |
+            | Translation-Four | Translation-Four.dashed.key-with-dash-two          |
+            | TranslationOne   | TranslationOne.Copyright                           |
+            | TranslationOne   | TranslationOne.DESCRIPTION                         |
+            | TranslationOne   | TranslationOne.last_operation_success              |
+            | TranslationOne   | TranslationOne.metaTags                            |
+            | TranslationOne   | TranslationOne.overflow_style                      |
+            | TranslationOne   | TranslationOne.subTitle                            |
+            | TranslationOne   | TranslationOne.title                               |
+            | TranslationThree | TranslationThree.alerts.CANCELED                   |
+            | TranslationThree | TranslationThree.alerts.DELETED                    |
+            | TranslationThree | TranslationThree.alerts.Updated                    |
+            | TranslationThree | TranslationThree.alerts.created                    |
+            | TranslationThree | TranslationThree.alerts.failed_insert              |
+            | TranslationThree | TranslationThree.alerts.missing_keys               |
+            | TranslationThree | TranslationThree.formErrors.edit.INVALID_TEXT      |
+            | TranslationThree | TranslationThree.formErrors.edit.empty_name        |
+            | TranslationThree | TranslationThree.formErrors.edit.missing_short_tag |
+            | TranslationThree | TranslationThree.formFields.edit.TEXT              |
+            | TranslationThree | TranslationThree.formFields.edit.name              |
+            | TranslationThree | TranslationThree.formFields.edit.short_tag         |
+            | TranslationThree | TranslationThree.formFields.new.TEXT               |
+            | TranslationThree | TranslationThree.formFields.new.name               |
+            | TranslationThree | TranslationThree.formFields.new.short_tag          |
+            +------------------+----------------------------------------------------+
+            TEXT_WRAP;
+    }
+
+    private function assertTranslationsExistAndHaveTranslatedKeys(): void
+    {
+        $this->assertFileExists(self::$languageTestPath . self::$locale . '/TranslationOne.php');
+        $this->assertFileExists(self::$languageTestPath . self::$locale . '/TranslationThree.php');
+        $this->assertFileExists(self::$languageTestPath . self::$locale . '/Translation-Four.php');
+
+        $translationOneKeys   = require self::$languageTestPath . self::$locale . '/TranslationOne.php';
+        $translationThreeKeys = require self::$languageTestPath . self::$locale . '/TranslationThree.php';
+        $translationFourKeys  = require self::$languageTestPath . self::$locale . '/Translation-Four.php';
+
+        $this->assertSame($translationOneKeys, $this->getActualTranslationOneKeys());
+        $this->assertSame($translationThreeKeys, $this->getActualTranslationThreeKeys());
+        $this->assertSame($translationFourKeys, $this->getActualTranslationFourKeys());
+    }
+
+    private function makeLocaleDirectory(): void
+    {
+        @mkdir(self::$languageTestPath . self::$locale, 0777, true);
+    }
+
+    private function clearGeneratedFiles(): void
+    {
+        if (is_file(self::$languageTestPath . self::$locale . '/TranslationOne.php')) {
+            unlink(self::$languageTestPath . self::$locale . '/TranslationOne.php');
+        }
+
+        if (is_file(self::$languageTestPath . self::$locale . '/TranslationThree.php')) {
+            unlink(self::$languageTestPath . self::$locale . '/TranslationThree.php');
+        }
+
+        if (is_file(self::$languageTestPath . self::$locale . '/Translation-Four.php')) {
+            unlink(self::$languageTestPath . self::$locale . '/Translation-Four.php');
+        }
+
+        if (is_dir(self::$languageTestPath . '/test_locale_incorrect')) {
+            rmdir(self::$languageTestPath . '/test_locale_incorrect');
+        }
+    }
+}
diff --git a/user_guide_src/source/changelogs/v4.5.0.rst b/user_guide_src/source/changelogs/v4.5.0.rst
index d18f0884e0ce..29c31dcabf8e 100644
--- a/user_guide_src/source/changelogs/v4.5.0.rst
+++ b/user_guide_src/source/changelogs/v4.5.0.rst
@@ -47,6 +47,8 @@ Enhancements
 Commands
 ========
 
+- Added ``spark lang:find`` command to update translations keys. See :ref:`generating-translation-files-via-command` for the details.
+
 Testing
 =======
 
diff --git a/user_guide_src/source/outgoing/localization.rst b/user_guide_src/source/outgoing/localization.rst
index f84e9b029004..837807989b0d 100644
--- a/user_guide_src/source/outgoing/localization.rst
+++ b/user_guide_src/source/outgoing/localization.rst
@@ -254,3 +254,44 @@ project:
 
 The translated messages will be automatically picked
 up because the translations folders get mapped appropriately.
+
+.. _generating-translation-files-via-command:
+
+Generating Translation Files via Command
+========================================
+
+.. versionadded:: 4.5.0
+
+You can automatically generate and update translation files in your **app** folder. The command will search for the use of the ``lang()`` function, combine the current translation keys in **app/Language** by defining the locale ``defaultLocale`` from ``Config\App``.
+After the operation, you need to translate the language keys yourself.
+The command is able to recognize nested keys normally ``File.array.nested.text``.
+Previously saved keys do not change.
+
+.. code-block:: console
+
+    php spark lang:find
+
+.. literalinclude:: localization/019.php
+
+.. note:: When the command scans folders, **app/Language** will be skipped.
+
+The language files generated will most likely not conform to your coding standards.
+It is recommended to format them. For example, run ``vendor/bin/php-cs-fixer fix ./app/Language`` if ``php-cs-fixer`` is installed.
+
+Before updating, it is possible to preview the translations found by the command:
+
+.. code-block:: console
+
+    php spark lang:find --verbose --show-new
+
+For a more accurate search, specify the desired locale or directory to scan.
+
+.. code-block:: console
+
+    php spark lang:find --dir Controllers/Translation --locale en --show-new
+
+Detailed information can be found by running the command:
+
+.. code-block:: console
+
+    php spark lang:find --help
diff --git a/user_guide_src/source/outgoing/localization/019.php b/user_guide_src/source/outgoing/localization/019.php
new file mode 100644
index 000000000000..5de7d9a80731
--- /dev/null
+++ b/user_guide_src/source/outgoing/localization/019.php
@@ -0,0 +1,13 @@
+<?php
+
+// Controllers/Translation/Lang.php
+$message  = lang('Text.info.success');
+$message2 = lang('Text.paragraph');
+
+// The following will be saved in Language/en/Text.php
+return [
+    'info' => [
+        'success' => 'Text.info.success',
+    ],
+    'paragraph' => 'Text.paragraph',
+];