diff --git a/framework/yii/base/Application.php b/framework/yii/base/Application.php
index 49b52d9..80e93a6 100644
--- a/framework/yii/base/Application.php
+++ b/framework/yii/base/Application.php
@@ -20,7 +20,7 @@ use yii\web\HttpException;
  * @property \yii\db\Connection $db The database connection. This property is read-only.
  * @property ErrorHandler $errorHandler The error handler application component. This property is read-only.
  * @property \yii\base\Formatter $formatter The formatter application component. This property is read-only.
- * @property \yii\i18n\I18N $i18N The internationalization component. This property is read-only.
+ * @property \yii\i18n\I18N $i18n The internationalization component. This property is read-only.
  * @property \yii\log\Logger $log The log component. This property is read-only.
  * @property \yii\web\Request|\yii\console\Request $request The request component. This property is read-only.
  * @property string $runtimePath The directory that stores runtime files. Defaults to the "runtime"
diff --git a/framework/yii/i18n/I18N.php b/framework/yii/i18n/I18N.php
index 61b0f77..fe0b533 100644
--- a/framework/yii/i18n/I18N.php
+++ b/framework/yii/i18n/I18N.php
@@ -14,6 +14,10 @@ use yii\base\InvalidConfigException;
 /**
  * I18N provides features related with internationalization (I18N) and localization (L10N).
  *
+ * @property MessageFormatter $messageFormatter The message formatter to be used to format message via ICU
+ * message format. Note that the type of this property differs in getter and setter. See
+ * [[getMessageFormatter()]] and [[setMessageFormatter()]] for details.
+ *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
@@ -69,7 +73,7 @@ class I18N extends Component
 	 * @param string $message the message to be translated.
 	 * @param array $params the parameters that will be used to replace the corresponding placeholders in the message.
 	 * @param string $language the language code (e.g. `en_US`, `en`).
-	 * @return string the translated message.
+	 * @return string the translated and formatted message.
 	 */
 	public function translate($category, $message, $params, $language)
 	{
@@ -93,8 +97,8 @@ class I18N extends Component
 		}
 
 		if (preg_match('~{\s*[\d\w]+\s*,~u', $message)) {
-			$formatter = new MessageFormatter();
-			$result = $formatter->format($language, $message, $params);
+			$formatter = $this->getMessageFormatter();
+			$result = $formatter->format($message, $params, $language);
 			if ($result === false) {
 				$errorMessage = $formatter->getErrorMessage();
 				Yii::warning("Formatting message for language '$language' failed with error: $errorMessage. The message being formatted was: $message.");
@@ -112,6 +116,35 @@ class I18N extends Component
 	}
 
 	/**
+	 * @var string|array|MessageFormatter
+	 */
+	private $_messageFormatter;
+
+	/**
+	 * Returns the message formatter instance.
+	 * @return MessageFormatter the message formatter to be used to format message via ICU message format.
+	 */
+	public function getMessageFormatter()
+	{
+		if ($this->_messageFormatter === null) {
+			$this->_messageFormatter = new MessageFormatter();
+		} elseif (is_array($this->_messageFormatter) || is_string($this->_messageFormatter)) {
+			$this->_messageFormatter = Yii::createObject($this->_messageFormatter);
+		}
+		return $this->_messageFormatter;
+	}
+
+	/**
+	 * @param string|array|MessageFormatter $value the message formatter to be used to format message via ICU message format.
+	 * Can be given as array or string configuration that will be given to [[Yii::createObject]] to create an instance
+	 * or a [[MessageFormatter]] instance.
+	 */
+	public function setMessageFormatter($value)
+	{
+		$this->_messageFormatter = $value;
+	}
+
+	/**
 	 * Returns the message source for the given category.
 	 * @param string $category the category name.
 	 * @return MessageSource the message source for the given category.
diff --git a/framework/yii/i18n/MessageFormatter.php b/framework/yii/i18n/MessageFormatter.php
index 55dc73d..d04782e 100644
--- a/framework/yii/i18n/MessageFormatter.php
+++ b/framework/yii/i18n/MessageFormatter.php
@@ -11,11 +11,13 @@ use yii\base\Component;
 use yii\base\NotSupportedException;
 
 /**
- * MessageFormatter enhances the message formatter class provided by PHP intl extension.
+ * MessageFormatter allows formatting messages via [ICU message format](http://userguide.icu-project.org/formatparse/messages)
+ *
+ * This class enhances the message formatter class provided by the PHP intl extension.
  *
  * The following enhancements are provided:
  *
- * - Accepts named arguments and mixed numeric and named arguments.
+ * - It accepts named arguments and mixed numeric and named arguments.
  * - Issues no error when an insufficient number of arguments have been provided. Instead, the placeholders will not be
  *   substituted.
  * - Fixes PHP 5.5 weird placeholder replacement in case no arguments are provided at all (https://bugs.php.net/bug.php?id=65920).
@@ -23,24 +25,18 @@ use yii\base\NotSupportedException;
  *   However it is highly recommended that you install [PHP intl extension](http://php.net/manual/en/book.intl.php) if you want
  *   to use MessageFormatter features.
  *
- * FallbackMessageFormatter is a fallback implementation for the PHP intl MessageFormatter that is
- * used in case PHP intl extension is not installed.
- *
- * Do not use this class directly. Use [[MessageFormatter]] instead, which will automatically detect
- * installed version of PHP intl and use the fallback if it is not installed.
- *
- * It is highly recommended that you install [PHP intl extension](http://php.net/manual/en/book.intl.php) if you want to use
- * MessageFormatter features.
+ *   The fallback implementation only supports the following message formats:
+ *   - plural formatting for english
+ *   - select format
+ *   - simple parameters
+ *   - integer number parameters
  *
- * This implementation only supports to following message formats:
- * - plural formatting for english
- * - select format
- * - simple parameters
+ *   The fallback implementation does NOT support the ['apostrophe-friendly' syntax](http://www.php.net/manual/en/messageformatter.formatmessage.php).
+ *   Also messages that are working with the fallback implementation are not necessarily compatible with the
+ *   PHP intl MessageFormatter so do not rely on the fallback if you are able to install intl extension somehow.
  *
- * The pattern also does NOT support the ['apostrophe-friendly' syntax](http://www.php.net/manual/en/messageformatter.formatmessage.php).
- *
- * Messages that can be parsed are also not necessarily compatible with the ICU formatting method so do not expect messages that work without intl installed
- * to work with intl
+ * @property string $errorCode Code of the last error. This property is read-only.
+ * @property string $errorMessage Description of the last error. This property is read-only.
  *
  * @author Alexander Makarov <sam@rmcreative.ru>
  * @author Carsten Brandt <mail@cebe.cc>
@@ -52,9 +48,9 @@ class MessageFormatter extends Component
 	private $_errorMessage = '';
 
 	/**
-	 * Get the error text from the last operation
+	 * Get the error code from the last operation
 	 * @link http://php.net/manual/en/messageformatter.geterrorcode.php
-	 * @return string Description of the last error.
+	 * @return string Code of the last error.
 	 */
 	public function getErrorCode()
 	{
@@ -72,34 +68,38 @@ class MessageFormatter extends Component
 	}
 
 	/**
-	 * Formats a message via ICU message format.
+	 * Formats a message via [ICU message format](http://userguide.icu-project.org/formatparse/messages)
+	 *
+	 * It uses the PHP intl extension's [MessageFormatter](http://www.php.net/manual/en/class.messageformatter.php)
+	 * and works around some issues.
+	 * If PHP intl is not installed a fallback will be used that supports a subset of the ICU message format.
 	 *
-	 * @link http://php.net/manual/en/messageformatter.formatmessage.php
+	 * @param string $pattern The pattern string to insert parameters into.
+	 * @param array $params The array of name value pairs to insert into the format string.
 	 * @param string $language The locale to use for formatting locale-dependent parts
-	 * @param string $message The pattern string to insert things into.
-	 * @param array $params The array of values to insert into the format string
 	 * @return string|boolean The formatted pattern string or `FALSE` if an error occurred
 	 */
-	public function format($language, $message, $params)
+	public function format($pattern, $params, $language)
 	{
 		$this->_errorCode = 0;
 		$this->_errorMessage = '';
 
 		if ($params === []) {
-			return $message;
+			return $pattern;
 		}
 
 		if (!class_exists('MessageFormatter', false)) {
-			return $this->fallbackFormat($language, $message, $params);
+			return $this->fallbackFormat($language, $pattern, $params);
 		}
 
 		if (version_compare(PHP_VERSION, '5.5.0', '<')) {
-			$message = $this->replaceNamedArguments($message, $params);
+			$pattern = $this->replaceNamedArguments($pattern, $params);
 			$params = array_values($params);
 		}
-		$formatter = new \MessageFormatter($language, $message);
+		$formatter = new \MessageFormatter($language, $pattern);
 		if ($formatter === null) {
-			$this->_errorMessage = "Unable to format message in language '$language'.";
+			$this->_errorCode = -1;
+			$this->_errorMessage = "Message pattern is invalid.";
 			return false;
 		}
 		$result = $formatter->format($params);
@@ -113,16 +113,19 @@ class MessageFormatter extends Component
 	}
 
 	/**
-	 * Parse input string according to a message pattern
+	 * Parses an input string according to an [ICU message format](http://userguide.icu-project.org/formatparse/messages) pattern.
 	 *
-	 * @link http://www.php.net/manual/en/messageformatter.parsemessage.php
+	 * It uses the PHP intl extension's [MessageFormatter::parse()](http://www.php.net/manual/en/messageformatter.parsemessage.php)
+	 * and works around some issues.
+	 * Usage of this method requires PHP intl extension to be installed.
+	 *
+	 * @param string $pattern The pattern to use for parsing the message.
+	 * @param string $message The message to parse, conforming to the pattern.
 	 * @param string $language The locale to use for formatting locale-dependent parts
-	 * @param string $pattern The pattern with which to parse the message.
-	 * @param array $message The message to parse, conforming to the pattern.
-	 * @return string|boolean An array containing items extracted, or `FALSE` on error.
+	 * @return array|boolean An array containing items extracted, or `FALSE` on error.
 	 * @throws \yii\base\NotSupportedException when PHP intl extension is not installed.
 	 */
-	public function parse($language, $pattern, $message)
+	public function parse($pattern, $message, $language)
 	{
 		$this->_errorCode = 0;
 		$this->_errorMessage = '';
@@ -138,7 +141,8 @@ class MessageFormatter extends Component
 //		}
 		$formatter = new \MessageFormatter($language, $pattern);
 		if ($formatter === null) {
-			$this->_errorMessage = "Unable to parse message in language '$language'.";
+			$this->_errorCode = -1;
+			$this->_errorMessage = "Message pattern is invalid.";
 			return false;
 		}
 		$result = $formatter->parse($message);
@@ -205,12 +209,12 @@ class MessageFormatter extends Component
 
 	/**
 	 * Fallback implementation for MessageFormatter::formatMessage
-	 * @param string $language The locale to use for formatting locale-dependent parts
-	 * @param string $message The pattern string to insert things into.
-	 * @param array $params The array of values to insert into the format string
+	 * @param string $pattern The pattern string to insert things into.
+	 * @param array $args The array of values to insert into the format string
+	 * @param string $locale The locale to use for formatting locale-dependent parts
 	 * @return string|boolean The formatted pattern string or `FALSE` if an error occurred
 	 */
-	protected function fallbackFormat($locale, $pattern, $args = [])
+	protected function fallbackFormat($pattern, $args, $locale)
 	{
 		if (($tokens = $this->tokenizePattern($pattern)) === false) {
 			return false;
diff --git a/framework/yii/log/Logger.php b/framework/yii/log/Logger.php
index 4e0e547..f79c40f 100644
--- a/framework/yii/log/Logger.php
+++ b/framework/yii/log/Logger.php
@@ -65,8 +65,8 @@ use yii\base\InvalidConfigException;
  * second element the total time spent in SQL execution. This property is read-only.
  * @property float $elapsedTime The total elapsed time in seconds for current request. This property is
  * read-only.
- * @property array $profiling The profiling results. Each array element has the following structure:
- * `[$token, $category, $time]`. This property is read-only.
+ * @property array $profiling The profiling results. Each array element has the following structure: `[$token,
+ * $category, $time]`. This property is read-only.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
diff --git a/tests/unit/framework/i18n/FallbackMessageFormatterTest.php b/tests/unit/framework/i18n/FallbackMessageFormatterTest.php
index 044c450..f674358 100644
--- a/tests/unit/framework/i18n/FallbackMessageFormatterTest.php
+++ b/tests/unit/framework/i18n/FallbackMessageFormatterTest.php
@@ -118,7 +118,7 @@ _MSG_
 	public function testNamedArgumentsObject($pattern, $expected, $args)
 	{
 		$formatter = new FallbackMessageFormatter();
-		$result = $formatter->format('en_US', $pattern, $args);
+		$result = $formatter->fallbackFormat($pattern, $args, 'en_US');
 		$this->assertEquals($expected, $result, $formatter->getErrorMessage());
 	}
 
@@ -127,9 +127,9 @@ _MSG_
 		$expected = '{'.self::SUBJECT.'} is '.self::N_VALUE;
 
 		$formatter = new FallbackMessageFormatter();
-		$result = $formatter->format('en_US', '{'.self::SUBJECT.'} is {'.self::N.'}', [
+		$result = $formatter->fallbackFormat('{'.self::SUBJECT.'} is {'.self::N.'}', [
 			self::N => self::N_VALUE,
-		]);
+		], 'en_US');
 
 		$this->assertEquals($expected, $result);
 	}
@@ -139,15 +139,15 @@ _MSG_
 		$pattern = '{'.self::SUBJECT.'} is '.self::N;
 
 		$formatter = new FallbackMessageFormatter();
-		$result = $formatter->format('en_US', $pattern, []);
+		$result = $formatter->fallbackFormat($pattern, [], 'en_US');
 		$this->assertEquals($pattern, $result, $formatter->getErrorMessage());
 	}
 }
 
 class FallbackMessageFormatter extends MessageFormatter
 {
-	public function fallbackFormat($locale, $pattern, $args = [])
+	public function fallbackFormat($pattern, $args, $locale)
 	{
-		return parent::fallbackFormat($locale, $pattern, $args);
+		return parent::fallbackFormat($pattern, $args, $locale);
 	}
 }
\ No newline at end of file
diff --git a/tests/unit/framework/i18n/MessageFormatterTest.php b/tests/unit/framework/i18n/MessageFormatterTest.php
index 5daaab9..9030d87 100644
--- a/tests/unit/framework/i18n/MessageFormatterTest.php
+++ b/tests/unit/framework/i18n/MessageFormatterTest.php
@@ -122,10 +122,10 @@ _MSG_
 	/**
 	 * @dataProvider patterns
 	 */
-	public function testNamedArgumentsObject($pattern, $expected, $args)
+	public function testNamedArguments($pattern, $expected, $args)
 	{
 		$formatter = new MessageFormatter();
-		$result = $formatter->format('en_US', $pattern, $args);
+		$result = $formatter->format($pattern, $args, 'en_US');
 		$this->assertEquals($expected, $result, $formatter->getErrorMessage());
 	}
 
@@ -134,9 +134,9 @@ _MSG_
 		$expected = '{'.self::SUBJECT.'} is '.self::N_VALUE;
 
 		$formatter = new MessageFormatter();
-		$result = $formatter->format('en_US', '{'.self::SUBJECT.'} is {'.self::N.', number}', [
+		$result = $formatter->format('{'.self::SUBJECT.'} is {'.self::N.', number}', [
 			self::N => self::N_VALUE,
-		]);
+		], 'en_US');
 
 		$this->assertEquals($expected, $result, $formatter->getErrorMessage());
 	}
@@ -145,7 +145,7 @@ _MSG_
 	{
 		$pattern = '{'.self::SUBJECT.'} is '.self::N;
 		$formatter = new MessageFormatter();
-		$result = $formatter->format('en_US', $pattern, []);
+		$result = $formatter->format($pattern, [], 'en_US');
 		$this->assertEquals($pattern, $result, $formatter->getErrorMessage());
 	}
 }
\ No newline at end of file