diff --git a/tests/unit/framework/LangTest.php b/tests/unit/framework/LangTest.php
index 2ca57cb61..094cb9843 100644
--- a/tests/unit/framework/LangTest.php
+++ b/tests/unit/framework/LangTest.php
@@ -4,30 +4,50 @@ class LangTest extends \Codeception\TestCase\Test
 {
 	public function testLang()
 	{
+		// Test separation of languages.
 		$ko = Rhymix\Framework\Lang::getInstance('ko');
 		$en = Rhymix\Framework\Lang::getInstance('en');
 		$this->assertTrue($ko instanceof Rhymix\Framework\Lang);
 		$this->assertTrue($en instanceof Rhymix\Framework\Lang);
 		$this->assertFalse($ko === $en);
 		
+		// Test backward compatible language code for Japanese.
 		$ja = Rhymix\Framework\Lang::getInstance('ja');
 		$jp = Rhymix\Framework\Lang::getInstance('jp');
 		$this->assertTrue($ja === $jp);
 		
-		$this->assertEquals('도움말', $ko->get('common.help'));
-		$this->assertEquals('Help', $en->get('common.help'));
-		$this->assertEquals('도움말', $ko->help);
-		$this->assertEquals('Help', $en->help);
-		
-		$this->assertEquals('common.nonexistent', $ko->get('common.nonexistent'));
-		$this->assertEquals('common.nonexistent', $ko->get('common.nonexistent', 'foo', 'bar'));
-		
-		$this->assertEquals('admin.help', $ko->get('admin.help'));
-		$this->assertEquals('admin.help', $en->get('admin.help'));
-		
+		// Test loading new plugins.
+		$this->assertNotEquals('ヘルプ', $ja->help);
 		$ja->loadPlugin('common');
 		$this->assertEquals('ヘルプ', $ja->help);
 		
+		// Test simple translations with namespacing.
+		$this->assertEquals('도움말', $ko->get('common.help'));
+		$this->assertEquals('Help', $en->get('common.help'));
+		
+		// Test simple translations without namespacing.
+		$this->assertEquals('도움말', $ko->help);
+		$this->assertEquals('Help', $en->help);
+		
+		// Test complex translations with multidimensional arrays.
+		$this->assertEquals('%d분 전', $ko->get('common.time_gap.min'));
+		$this->assertEquals('10분 전', $ko->get('common.time_gap.min', 10));
+		$this->assertTrue($ko->get('common.time_gap') instanceof \ArrayObject);
+		$this->assertEquals('%d분 전', $ko->get('common.time_gap')->min);
+		
+		// Test nonexistent keys.
+		$this->assertEquals('common.nonexistent', $ko->get('common.nonexistent'));
+		$this->assertEquals('common.nonexistent', $ko->get('common.nonexistent', 'foo', 'bar'));
+		$this->assertEquals('admin.help', $ko->get('admin.help'));
+		$this->assertEquals('admin.help', $en->get('admin.help'));
+		
+		// Test fallback to English.
+		$en->only_in_english = 'Hello world';
+		$this->assertEquals('Hello world', $ko->only_in_english);
+		$this->assertEquals('Hello world', $en->only_in_english);
+		$this->assertEquals('Hello world', $ja->only_in_english);
+		
+		// Test string interpolation.
 		$ko->foobartestlang = '%s님 안녕하세요?';
 		$this->assertEquals('Travis님 안녕하세요?', $ko->foobartestlang('Travis'));
 		$en->foobartestlang = 'Hello, %s!';