1) Added new content to readme file. 2) Added log4j logger to method updateUnknowWord(). 3) Added two new utility methods into DataHolder class, which are getWordPOSEntries(), updateWordPOS(). 4) Fixed a bug in method markKnown(). 5) Fixed a bug in method updatePOS(). 6) Override toString() method in WordPOSKey class and WordPOSValue class.