diff --git a/src/application/config/autoload.php b/src/application/config/autoload.php
index 521ab1c7..20541f46 100644
--- a/src/application/config/autoload.php
+++ b/src/application/config/autoload.php
@@ -96,7 +96,7 @@ $autoload['config'] = array();
 |
 */
 
-$autoload['language'] = array('translations');
+$autoload['language'] = array();
 
 
 /*
diff --git a/src/application/config/config.php b/src/application/config/config.php
index 33e50075..a68a8dad 100644
--- a/src/application/config/config.php
+++ b/src/application/config/config.php
@@ -86,7 +86,8 @@ $config['url_suffix'] = '';
 | than english.
 |
 */
-$config['language']	= 'greek';//'english';
+$config['language']	= 'english'; // default language
+$config['available_languages'] = array('english', 'german', 'greek');
 
 /*
 |--------------------------------------------------------------------------
diff --git a/src/application/controllers/appointments.php b/src/application/controllers/appointments.php
index 133fb6fb..564a96e7 100644
--- a/src/application/controllers/appointments.php
+++ b/src/application/controllers/appointments.php
@@ -1,6 +1,18 @@
 <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 
 class Appointments extends CI_Controller {
+	public function __construct() {
+		parent::__construct();
+		$this->load->library('session');
+		// Set user's selected language.
+		if ($this->session->userdata('language')) {
+			$this->config->set_item('language', $this->session->userdata('language'));
+			$this->lang->load('translations', $this->session->userdata('language'));
+		} else {
+			$this->lang->load('translations', $this->config->item('language')); // default
+		}
+	}
+	
     /**
      * Default callback method of the application. 
      * 
diff --git a/src/application/controllers/backend.php b/src/application/controllers/backend.php
index 407bf919..038e82a3 100644
--- a/src/application/controllers/backend.php
+++ b/src/application/controllers/backend.php
@@ -4,6 +4,14 @@ class Backend extends CI_Controller {
     public function __construct() {
         parent::__construct();
         $this->load->library('session');
+		
+		// Set user's selected language.        
+        if ($this->session->userdata('language')) {
+        	$this->config->set_item('language', $this->session->userdata('language'));
+        	$this->lang->load('translations', $this->session->userdata('language'));
+        } else {
+        	$this->lang->load('translations', $this->config->item('language')); // default
+        }	
     }
     
     /**
diff --git a/src/application/controllers/backend_api.php b/src/application/controllers/backend_api.php
index 05ec1807..2b73d9db 100644
--- a/src/application/controllers/backend_api.php
+++ b/src/application/controllers/backend_api.php
@@ -1038,6 +1038,40 @@ class Backend_api extends CI_Controller {
             ));
         }
     }
+    
+    /**
+     * [AJAX] Change system language for current user.
+     * 
+     * The language setting is stored in session data and retrieved every time the user
+     * visits any of the system pages.
+     * 
+     * @param string $_POST['language'] Selected language name.
+     */
+    public function ajax_change_language() {
+    	try {
+    		// Check if language exists in the available languages.
+    		$found = false;
+    		foreach($this->config->item('available_languages') as $lang) {
+    			if ($lang == $_POST['language']) {
+    				$found = true;
+    				break;
+    			}	
+    		}
+    		
+    		if (!$found)
+    			throw new Exception('Translations for the given language does not exist (' . $_POST['language'] . ').');
+    		
+    		$this->session->set_userdata('language', $_POST['language']);
+    		$this->config->set_item('language', $_POST['language']);
+    		
+    		echo json_encode(AJAX_SUCCESS);
+    		
+    	} catch(Exception $exc) {
+    		echo json_encode(array(
+                'exceptions' => array(exceptionToJavaScript($exc))
+            )); 
+    	}
+    }
 }
 
 /* End of file backend_api.php */
diff --git a/src/application/controllers/errors.php b/src/application/controllers/errors.php
index 8e429b40..7ead0770 100644
--- a/src/application/controllers/errors.php
+++ b/src/application/controllers/errors.php
@@ -1,6 +1,18 @@
 <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 
 class Errors extends CI_Controller {
+	public function __construct() {
+		parent::__construct();
+		$this->load->library('session');
+		// Set user's selected language.
+		if ($this->session->userdata('language')) {
+			$this->config->set_item('language', $this->session->userdata('language'));
+			$this->lang->load('translations', $this->session->userdata('language'));
+		} else {
+			$this->lang->load('translations', $this->config->item('language')); // default
+		}
+	}
+	
     public function index() {
         $this->e404();
     }
diff --git a/src/application/controllers/google.php b/src/application/controllers/google.php
index 80e95639..8dc0f5a3 100644
--- a/src/application/controllers/google.php
+++ b/src/application/controllers/google.php
@@ -1,6 +1,10 @@
 <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 
 class Google extends CI_Controller {
+	public function __construct() {
+		parent::__construct();
+	}
+	
     /**
      * Authorize Google Calendar API usage for a specific provider.
      * 
diff --git a/src/application/controllers/user.php b/src/application/controllers/user.php
index 6e6a59fe..fdf1d626 100644
--- a/src/application/controllers/user.php
+++ b/src/application/controllers/user.php
@@ -4,6 +4,14 @@ class User extends CI_Controller {
     public function __construct() {
         parent::__construct();
         $this->load->library('session');
+        
+        // Set user's selected language.
+        if ($this->session->userdata('language')) {
+        	$this->config->set_item('language', $this->session->userdata('language'));
+        	$this->lang->load('translations', $this->session->userdata('language'));
+        } else {
+        	$this->lang->load('translations', $this->config->item('language')); // default
+        }
     }
     
     public function index() {
diff --git a/src/application/language/english/translations_lang.php b/src/application/language/english/translations_lang.php
index 627915d3..45907558 100644
--- a/src/application/language/english/translations_lang.php
+++ b/src/application/language/english/translations_lang.php
@@ -143,7 +143,7 @@ $lang['secretary_deleted'] = 'Secretary deleted successfully!';
 $lang['service_saved'] = 'Service saved successfully!';
 $lang['service_category_saved'] = 'Service category saved successfully!';
 $lang['service_deleted'] = 'Service deleted successfully!';
-$lang['servce_category_deleted'] = 'Service category deleted successfully!';
+$lang['service_category_deleted'] = 'Service category deleted successfully!';
 $lang['customer_saved'] = 'Customer saved successfully!';
 $lang['customer_deleted'] = 'Customer deleted successfully!';
 $lang['current_view'] = 'Current View';
diff --git a/src/application/language/german/translations_lang.php b/src/application/language/german/translations_lang.php
index 29113151..902fe637 100644
--- a/src/application/language/german/translations_lang.php
+++ b/src/application/language/german/translations_lang.php
@@ -143,7 +143,7 @@ $lang['secretary_deleted'] = 'Bearbeiter erfolgreich gelöscht!';
 $lang['service_saved'] = 'Dienstleistung erfolgreich gesichert!';
 $lang['service_category_saved'] = 'Dienstleistungskategorie erfolgreich gesichert!';
 $lang['service_deleted'] = 'Dienstleistung erfolgreich gelöscht!';
-$lang['servce_category_deleted'] = 'Dienstleistungskategorie erfolgreicht gelöscht!';
+$lang['service_category_deleted'] = 'Dienstleistungskategorie erfolgreicht gelöscht!';
 $lang['customer_saved'] = 'Kunde erfolgreich gesichert!';
 $lang['customer_deleted'] = 'Kunde erfolgreich gelöscht!';
 $lang['current_view'] = 'Laufende Ansicht';
diff --git a/src/application/language/greek/translations_lang.php b/src/application/language/greek/translations_lang.php
index 62cc135a..159c7e99 100644
--- a/src/application/language/greek/translations_lang.php
+++ b/src/application/language/greek/translations_lang.php
@@ -143,7 +143,7 @@ $lang['secretary_deleted'] = 'Ο γραμματέας διαγράφηκε επ
 $lang['service_saved'] = 'Η υπηρεσία αποθηκεύτηκε επιτυχώς!';
 $lang['service_category_saved'] = 'Η κατηγορία υπηρεσιών αποθηκεύτηκε επιτυχώς!';
 $lang['service_deleted'] = 'Η υπηρεσία διαγράφηκε επιτυχώς!';
-$lang['servce_category_deleted'] = 'Η κατηγορία υπηρεσιών διαγράφηκε επιτυχώς!';
+$lang['service_category_deleted'] = 'Η κατηγορία υπηρεσιών διαγράφηκε επιτυχώς!';
 $lang['customer_saved'] = 'Ο πελάτης αποθηκεύτηκε επιτυχώς!';
 $lang['customer_deleted'] = 'Ο πελάτης διαγράφηκε επιτυχώς!';
 $lang['current_view'] = 'Τρέχων Προβολή';
diff --git a/src/application/views/backend/calendar.php b/src/application/views/backend/calendar.php
index 1bab70eb..4102b081 100644
--- a/src/application/views/backend/calendar.php
+++ b/src/application/views/backend/calendar.php
@@ -27,8 +27,6 @@
         }
     };
     
-    var EALang = <?php echo json_encode($this->lang->language); ?>;
-    
     $(document).ready(function() {
         BackendCalendar.initialize(true);
     });
diff --git a/src/application/views/backend/customers.php b/src/application/views/backend/customers.php
index 214404dd..221c1622 100644
--- a/src/application/views/backend/customers.php
+++ b/src/application/views/backend/customers.php
@@ -18,8 +18,6 @@
         }
     };
     
-    var EALang = <?php echo json_encode($this->lang->language); ?>
-    
     $(document).ready(function() {
         BackendCustomers.initialize(true);
     });
diff --git a/src/application/views/backend/footer.php b/src/application/views/backend/footer.php
index ae076553..030a32dd 100644
--- a/src/application/views/backend/footer.php
+++ b/src/application/views/backend/footer.php
@@ -12,7 +12,10 @@
                 }
             ?>
         </a> | 
-        <?php echo $this->lang->line('licensed_under'); ?> GPLv3
+        <?php echo $this->lang->line('licensed_under'); ?> GPLv3 |
+        <span id="select-language" class="badge badge-inverse">
+        	<?php echo ucfirst($this->config->item('language')); ?>
+        </span>
     </div>
     
     <div id="footer-user-display-name">
diff --git a/src/application/views/backend/header.php b/src/application/views/backend/header.php
index c748ec88..a312a0f7 100644
--- a/src/application/views/backend/header.php
+++ b/src/application/views/backend/header.php
@@ -64,6 +64,12 @@
     <script 
         type="text/javascript" 
         src="<?php echo $base_url; ?>assets/js/libs/jquery/jquery.mousewheel.js"></script>
+        
+    <script type="text/javascript">
+    	// Global JavaScript Variables - Used in all backend pages.
+    	var availableLanguages = <?php echo json_encode($this->config->item('available_languages')); ?>;
+    	var EALang = <?php echo json_encode($this->lang->language); ?>;
+    </script>
 </head>
 
 <body>
diff --git a/src/application/views/backend/services.php b/src/application/views/backend/services.php
index 8d6687a4..54c5ec9b 100644
--- a/src/application/views/backend/services.php
+++ b/src/application/views/backend/services.php
@@ -14,8 +14,6 @@
         }
     };
     
-    var EALang = <?php echo json_encode($this->lang->language); ?>;
-    
     $(document).ready(function() {
         BackendServices.initialize(true);
     });
diff --git a/src/application/views/backend/settings.php b/src/application/views/backend/settings.php
index 193b2af8..2fc4a12c 100644
--- a/src/application/views/backend/settings.php
+++ b/src/application/views/backend/settings.php
@@ -23,8 +23,6 @@
         }
     };
     
-    var EALang = <?php echo json_encode($this->lang->language); ?>;
-    
     $(document).ready(function() {
         BackendSettings.initialize(true);
     });
diff --git a/src/application/views/backend/users.php b/src/application/views/backend/users.php
index 0d5687af..8e01f5fc 100644
--- a/src/application/views/backend/users.php
+++ b/src/application/views/backend/users.php
@@ -31,8 +31,6 @@
             'privileges': <?php echo json_encode($privileges); ?>
         }
     };
-
-    var EALang = <?php echo json_encode($this->lang->language); ?>;
     
     $(document).ready(function() {
         BackendUsers.initialize(true);
diff --git a/src/application/views/general/installation.php b/src/application/views/general/installation.php
index 77cd1c97..9a54c142 100644
--- a/src/application/views/general/installation.php
+++ b/src/application/views/general/installation.php
@@ -2,9 +2,9 @@
 <html>
 <head>
     <?php // PAGE META ?>
-    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
     <title>Easy!Appointments - Installation</title>
-
+    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
+    
     <?php // INCLUDE CSS ?>
     <link 
         rel="stylesheet" 
@@ -31,16 +31,15 @@
     <script 
         type="text/javascript" 
         src="<?php echo $base_url; ?>assets/js/libs/date.js"></script>
-    <script 
-        type="text/javascript" 
-        src="<?php echo $base_url; ?>assets/js/general_functions.js"></script>
     
     <script type="text/javascript">
-        $(document).ready(function() {
-            var GlobalVariables = {
-                'baseUrl': <?php echo '"' . $base_url . '"'; ?>
-            };
-            
+	    var GlobalVariables = {
+            'baseUrl': <?php echo '"' . $base_url . '"'; ?>
+        };
+
+        var EALang = <?php echo json_encode($this->lang->language); ?>;
+        
+        $(document).ready(function() {            
             var MIN_PASSWORD_LENGTH = 7;
             var AJAX_SUCCESS = 'SUCCESS';
             var AJAX_FAILURE = 'FAILURE';
@@ -59,7 +58,7 @@
             $('#install').click(function() {
                 if (!validate()) return;
         
-                var postUrl = GlobalVariables.baseUrl + 'appointments/ajax_install';
+                var postUrl = GlobalVariables.baseUrl + 'index.php/appointments/ajax_install';
                 var postData = {
                     'admin': JSON.stringify(getAdminData()),
                     'company': JSON.stringify(getCompanyData())
@@ -310,5 +309,9 @@
     <footer>
         Powered by <a href="http://easyappointments.org">Easy!Appointments</a>
     </footer>
+    
+    <script 
+        type="text/javascript" 
+        src="<?php echo $base_url; ?>assets/js/general_functions.js"></script>
 </body>
 </html>
\ No newline at end of file
diff --git a/src/assets/css/backend.css b/src/assets/css/backend.css
index 2122efa7..34324afb 100644
--- a/src/assets/css/backend.css
+++ b/src/assets/css/backend.css
@@ -571,6 +571,12 @@ padding: 4px 7px;
     margin-bottom: 0px;
 }
 
+#users-page .editable form,
+#users-page .editable select, 
+#users-page .editable input {
+	margin: 0px;
+}
+
 /* BACKEND SETTINGS PAGE
    -------------------------------------------------------------------- */
 #settings-page h2 {
diff --git a/src/assets/css/general.css b/src/assets/css/general.css
index 7ccebb2b..202bcd21 100644
--- a/src/assets/css/general.css
+++ b/src/assets/css/general.css
@@ -45,6 +45,15 @@ body .ui-icon, .ui-widget-content .ui-icon {
     background-image: url(libs/jquery/images/ui-icons_52b799_256x240.png);
 }
 
+li.language:hover {
+	cursor: pointer;
+	color: #005580;
+}
+
+#select-language {
+	cursor: pointer;
+}
+
 /* JQUERY UI DATETIME PICKER ADDON
    ------------------------------------------------------------------------- */
 .ui-timepicker-div .ui-widget-header { margin-bottom: 8px; }
diff --git a/src/assets/js/backend.js b/src/assets/js/backend.js
index 2e6e3945..25f1b847 100644
--- a/src/assets/js/backend.js
+++ b/src/assets/js/backend.js
@@ -23,6 +23,8 @@ $(document).ready(function() {
             classes: 'qtip-green qtip-shadow custom-qtip'
         }
     });
+    
+    GeneralFunctions.enableLanguageSelection($('#select-language'));
 });
 
 /**
diff --git a/src/assets/js/backend_calendar.js b/src/assets/js/backend_calendar.js
index 8f1e5fc7..778d0252 100644
--- a/src/assets/js/backend_calendar.js
+++ b/src/assets/js/backend_calendar.js
@@ -41,13 +41,42 @@ var BackendCalendar = {
             'titleFormat': {
                 'month': 'MMMM yyyy',
                 'week': "MMMM d[ yyyy]{ '&#8212;'[ MMM] d, yyyy}",
-                'day': 'dddd, MMM d, yyyy'
+                'day': 'dddd, MMMM d, yyyy'
             },
             'header': {
                 'left': 'prev,next today',
                 'center': 'title',
                 'right': 'agendaDay,agendaWeek,month'
             },
+            
+            // Translations
+            'monthNames': [EALang['january'], EALang['february'], EALang['march'], EALang['april'],
+                           EALang['may'], EALang['june'], EALang['july'], EALang['august'], 
+                           EALang['september'],EALang['october'], EALang['november'], 
+                           EALang['december']],
+           	'monthNamesShort': [EALang['january'].substr(0,3), EALang['february'].substr(0,3), 
+           	        EALang['march'].substr(0,3), EALang['april'].substr(0,3),
+                    EALang['may'].substr(0,3), EALang['june'].substr(0,3), 
+                    EALang['july'].substr(0,3), EALang['august'].substr(0,3), 
+                    EALang['september'].substr(0,3),EALang['october'].substr(0,3), 
+                    EALang['november'].substr(0,3), EALang['december'].substr(0,3)],
+            'dayNames': [EALang['sunday'], EALang['monday'], EALang['tuesday'], EALang['wednesday'], 
+	                    EALang['thursday'], EALang['friday'], EALang['saturday']],
+	        'dayNamesShort': [EALang['sunday'].substr(0,3), EALang['monday'].substr(0,3), 
+	               EALang['tuesday'].substr(0,3), EALang['wednesday'].substr(0,3), 
+	               EALang['thursday'].substr(0,3), EALang['friday'].substr(0,3),
+	               EALang['saturday'].substr(0,3)],
+	        'dayNamesMin': [EALang['sunday'].substr(0,2), EALang['monday'].substr(0,2), 
+	               EALang['tuesday'].substr(0,2), EALang['wednesday'].substr(0,2), 
+	               EALang['thursday'].substr(0,2), EALang['friday'].substr(0,2),
+	               EALang['saturday'].substr(0,2)],
+            'buttonText': {
+            	'today': EALang['today'],
+            	'day': EALang['day'],
+            	'week': EALang['week'],
+            	'month': EALang['month']
+            },
+	         
             // Calendar events need to be declared on initialization.
             'windowResize': BackendCalendar.calendarWindowResize,
             'viewDisplay': BackendCalendar.calendarViewDisplay,
@@ -60,13 +89,6 @@ var BackendCalendar = {
             }   
         });
         
-        // Temporary fix: make the first letter capital in all the lowercase strings
-        // of the calendar.
-        $('#calendar .fc-button-today').text('Today');
-        $('#calendar .fc-button-agendaDay').text('Day');
-        $('#calendar .fc-button-agendaWeek').text('Week');
-        $('#calendar .fc-button-month').text('Month');
-        
         // Trigger once to set the proper footer position after calendar 
         // initialization.
         BackendCalendar.calendarWindowResize(); 
@@ -1488,7 +1510,7 @@ var BackendCalendar = {
         });
         
         BackendCalendar.lastFocusedEventData = event;
-        $(jsEvent.target).popover('show');
+        $(jsEvent.target).popover('toggle');
         
         // Fix popover position
         if ($('.popover').position().top < 200) $('.popover').css('top', '200px');
diff --git a/src/assets/js/backend_services.js b/src/assets/js/backend_services.js
index dd56f8e9..92e29a2d 100644
--- a/src/assets/js/backend_services.js
+++ b/src/assets/js/backend_services.js
@@ -316,9 +316,10 @@ ServicesHelper.prototype.validate = function(service) {
                 missingRequired = true;
             }
         });
-        if (missingRequired) {
+        
+        if (missingRequired) 
             throw EALang['fields_are_required'];
-        }
+        
         
         return true;
     } catch(exc) {
@@ -541,14 +542,13 @@ CategoriesHelper.prototype.bindEventHandlers = function() {
     $('#delete-category').click(function() {
         var categoryId = $('#category-id').val();
 
-        var messageBtns = {
-            'Delete': function() {
-                BackendServices.helper.delete(categoryId);
-                $('#message_box').dialog('close');
-            },
-            'Cancel': function() {
-                $('#message_box').dialog('close');
-            }
+        var messageBtns = {};
+        messageBtns[EALang['delete']] = function() {
+            BackendServices.helper.delete(categoryId);
+            $('#message_box').dialog('close');
+        };
+        messageBtns[EALang['cancel']] = function() {
+            $('#message_box').dialog('close');
         };
 
         GeneralFunctions.displayMessageBox(EALang['delete_category'], 
@@ -642,7 +642,7 @@ CategoriesHelper.prototype.save = function(category) {
         
         if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
-        Backend.displayNotification(EALang['category_saved']);
+        Backend.displayNotification(EALang['service_category_saved']);
         BackendServices.helper.resetForm();
         $('#filter-categories .key').val('');
         BackendServices.helper.filter('', response.id, true);
@@ -666,7 +666,7 @@ CategoriesHelper.prototype.delete = function(id) {
         
         if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
-        Backend.displayNotification(EALang['category_deleted']);
+        Backend.displayNotification(EALang['service_category_deleted']);
         
         BackendServices.helper.resetForm();
         BackendServices.helper.filter($('#filter-categories .key').val());
diff --git a/src/assets/js/general_functions.js b/src/assets/js/general_functions.js
index 070dadc0..9303bc05 100644
--- a/src/assets/js/general_functions.js
+++ b/src/assets/js/general_functions.js
@@ -268,5 +268,54 @@ var GeneralFunctions = {
         }
         
         return true;
+    },
+    
+    /**
+     * Enables the language selection functionality. Must be called on every page has a
+     * language selection button. This method requires the global variable 'availableLanguages'
+     * to be initialized before the execution.
+     * 
+     * @param {object} $element Selected element button for the language selection.
+     */
+    enableLanguageSelection: function($element) {
+    	// Select Language
+        var html = '<ul id="language-list">';
+        $.each(availableLanguages, function() {
+        	html += '<li class="language" data-language="' + this + '">' 
+        			+ GeneralFunctions.ucaseFirstLetter(this) + '</li>';
+        });
+        html += '</ul>';
+        
+        $element.popover({
+            'placement': 'top',
+            'title': 'Select Language',
+            'content': html,
+            'html': true,
+            'container': 'body',
+            'trigger': 'manual'
+        });
+        
+        $element.click(function() {
+        	if ($('#language-list').length == 0) {
+        		$(this).popover('show');
+        	} else {
+        		$(this).popover('hide');
+        	}
+        });
+        
+        $(document).on('click', 'li.language', function() {
+        	// Change language with ajax call and refresh page.
+        	var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_change_language';
+        	var postData = { 'language': $(this).attr('data-language') };
+        	$.post(postUrl, postData, function(response) {
+        		////////////////////////////////////////////////////
+        		console.log('Change Language Response', response);
+    			////////////////////////////////////////////////////
+        		
+        		if (!GeneralFunctions.handleAjaxExceptions(response)) return;
+        		document.location.reload(true);
+        		
+        	}, 'json');
+        });
     }
 };
\ No newline at end of file
diff --git a/src/assets/js/working_plan.js b/src/assets/js/working_plan.js
index f48ad7c4..b9b6a2d3 100644
--- a/src/assets/js/working_plan.js
+++ b/src/assets/js/working_plan.js
@@ -276,7 +276,7 @@ WorkingPlan.prototype.bindEventHandlers = function() {
  */
 WorkingPlan.prototype.get = function() {
     var workingPlan = {};
-    $('.working-plan input[type="checkbox"').each(function() {
+    $('.working-plan input[type="checkbox"]').each(function() {
         var id = $(this).attr('id');
         if ($(this).prop('checked') == true) {
             workingPlan[id] = {};