diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ffba4a..f3f8d41 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,8 +4,13 @@
 
 ### Added
 
+- Support for fallback locale when using `RRule::humanReadable()` [#11](https://github.com/rlanvin/php-rrule/pull/11)
 - Dutch translation (NL) [#9](https://github.com/rlanvin/php-rrule/pull/9)
 
+### Fixed
+
+- Fixed fatal error Locale class not found when intl extension is not loaded [#11](https://github.com/rlanvin/php-rrule/pull/11)
+
 ## [1.1.0] - 2016-03-30
 
 ### Added
@@ -40,4 +45,4 @@
 
 [Unreleased]: https://github.com/rlanvin/php-rrule/compare/v1.1.0...HEAD
 [1.1.0]: https://github.com/rlanvin/php-rrule/compare/v1.0.1...v1.1.0
-[1.0.1]: https://github.com/rlanvin/php-rrule/compare/v1.0.0...v1.0.1
\ No newline at end of file
+[1.0.1]: https://github.com/rlanvin/php-rrule/compare/v1.0.0...v1.0.1
diff --git a/src/RRule.php b/src/RRule.php
index 67a879c..f18af6e 100755
--- a/src/RRule.php
+++ b/src/RRule.php
@@ -2016,10 +2016,16 @@ class RRule implements RRuleInterface
 	 * Will load the basic first (e.g. "en") and then the region-specific if any
 	 * (e.g. "en_GB"), merging as necessary.
 	 * So region-specific translation files don't need to redefine every strings.
+	 *
+	 * @param string      $locale
+	 * @param string|null $fallback
+	 *
+	 * @return array
+	 * @throws \InvalidArgumentException
 	 */
-	static protected function i18nLoad($locale)
+	static protected function i18nLoad($locale, $fallback = null)
 	{
-		if ( ! preg_match('/^([a-z]{2})(_[A-Z]{2})?$/', $locale, $matches) ) {
+		if ( ! preg_match('/^([a-z]{2})(_[A-Z]{2})?(?:_[A-Z]*)?(?:\.[a-zA-Z\-0-8]*)?$/', $locale, $matches) ) {
 			throw new \InvalidArgumentException('The locale option does not look like a valid locale: '.$locale);
 		}
 
@@ -2045,6 +2051,9 @@ class RRule implements RRuleInterface
 		}
 
 		if ( empty($result) ) {
+			if (!is_null($fallback)) {
+				return self::i18nLoad($fallback);
+			}
 			throw new \InvalidArgumentException("Failed to load translations for '$locale'");
 		}
 
@@ -2054,6 +2063,10 @@ class RRule implements RRuleInterface
 	/**
 	 * Format a rule in a human readable string
 	 * intl extension is required.
+	 *
+	 * @param array  $opt
+	 *
+	 * @return string
 	 */
 	public function humanReadable(array $opt = array())
 	{
@@ -2061,9 +2074,17 @@ class RRule implements RRuleInterface
 			self::$intl_loaded = extension_loaded('intl');
 		}
 
+		$locale = setlocale(LC_MESSAGES, 0);
+		if ( self::$intl_loaded ) {
+			$locale = \Locale::getDefault();
+		} else if ($locale == 'C') {
+			$locale = 'en';
+		}
+
 		$default_opt = array(
-			'locale' => \Locale::getDefault(),
-			'date_formatter' => null
+			'locale' => $locale,
+			'date_formatter' => null,
+			'fallback' => 'en',
 		);
 
 		if ( self::$intl_loaded ) {
@@ -2104,7 +2125,7 @@ class RRule implements RRuleInterface
 			}
 		}
 
-		$i18n = self::i18nLoad($opt['locale']);
+		$i18n = self::i18nLoad($opt['locale'], $opt['fallback']);
 
 		$parts = array(
 			'freq' => '',
@@ -2323,5 +2344,4 @@ class RRule implements RRuleInterface
 		$str = implode('',$parts);
 		return $str;
 	}
-
 }
diff --git a/tests/RRuleTest.php b/tests/RRuleTest.php
index 910c053..060293e 100755
--- a/tests/RRuleTest.php
+++ b/tests/RRuleTest.php
@@ -1943,4 +1943,88 @@ class RRuleTest extends PHPUnit_Framework_TestCase
 		$this->assertEquals(date_create('2007-01-01'), $rrule[0], 'No modification possible with getOccurences (cached version)');
 
 	}
+
+	/**
+	 * Providing a set of valid locales to call RRule::i18nLoad() with
+	 *
+	 * @return array
+	 */
+	public function validFallbackLocales()
+	{
+		return array(
+			array('en'),
+			array('fr'),
+			array('en_US'),
+			array('en_US_POSIX'),
+			array('en_US.utf-8'),
+		);
+	}
+
+	/**
+	 * Test that the RRule::i18nLoad() does not fail when provided with valid locales
+	 *
+	 * @dataProvider validFallbackLocales
+	 */
+	public function testHumanReadable($fallback)
+	{
+		$date = date_create('2007-01-01');
+		$rrule = new RRule(array(
+			'freq' => 'daily',
+			'count' => 10,
+			'dtstart' => $date
+		));
+
+		$reflector = new ReflectionClass('RRule\RRule');
+
+		// Force RRule::$intl_loaded to false, to test fallback locales
+		$property = $reflector->getProperty('intl_loaded');
+		$property->setAccessible(true);
+		$property->setValue($rrule, false);
+
+		$method = $reflector->getMethod('humanReadable');
+		$result = $method->invokeArgs($rrule, array(array('locale' => 'xx', 'fallback' => $fallback)));
+		$this->assertNotEmpty($result);
+	}
+
+	/**
+	 * Providing a set of invalid locales to call RRule::i18nLoad() with
+	 *
+	 * @return array
+	 */
+	public function invalidFallbackLocales()
+	{
+		return array(
+			array('xx', 'eng'),
+			array('xx', 'invalid'),
+			array('xx', null),
+			array(null, null),
+			array(null, 'en_US._wr!ng'),
+		);
+	}
+
+	/**
+	 * Tests that the RRule::i18nLoad() fails as expected on invalid $locale settings
+	 *
+	 * @dataProvider invalidFallbackLocales
+	 * @expectedException \InvalidArgumentException
+	 */
+	public function testHumanReadableFails($locale, $fallback)
+	{
+		$date = date_create('2007-01-01');
+		$rrule = new RRule(array(
+			'freq' => 'daily',
+			'count' => 10,
+			'dtstart' => $date
+		));
+
+		$reflector = new ReflectionClass('RRule\RRule');
+
+		// Force RRule::$intl_loaded to false, to test fallback locales
+		$property = $reflector->getProperty('intl_loaded');
+		$property->setAccessible(true);
+		$property->setValue($rrule, false);
+
+		$method = $reflector->getMethod('humanReadable');
+		$method->invokeArgs($rrule, array(array('locale' => $locale, 'fallback' => $fallback)));
+	}
 }