diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index a026939053..2ec245ea22 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.50 under development
 ------------------------
 
+- Bug #19927: Fixed `console\controllers\MessageController` when saving translations to database: fixed FK error when adding new string and language at the same time, checking/regenerating all missing messages and dropping messages for unused languages (atrandafir)
 - Enh #12743: Added new methods `BaseActiveRecord::loadRelations()` and `BaseActiveRecord::loadRelationsFor()` to eager load related models for existing primary model instances (PowerGamer1)
 
 
diff --git a/framework/console/controllers/MessageController.php b/framework/console/controllers/MessageController.php
index e1a7357690..6d5a7d6448 100644
--- a/framework/console/controllers/MessageController.php
+++ b/framework/console/controllers/MessageController.php
@@ -353,17 +353,7 @@ EOD;
         foreach ($rows as $row) {
             $currentMessages[$row['category']][$row['id']] = $row['message'];
         }
-
-        $currentLanguages = [];
-        $rows = (new Query())->select(['language'])->from($messageTable)->groupBy('language')->all($db);
-        foreach ($rows as $row) {
-            $currentLanguages[] = $row['language'];
-        }
-        $missingLanguages = [];
-        if (!empty($currentLanguages)) {
-            $missingLanguages = array_diff($languages, $currentLanguages);
-        }
-
+        
         $new = [];
         $obsolete = [];
 
@@ -372,89 +362,130 @@ EOD;
 
             if (isset($currentMessages[$category])) {
                 $new[$category] = array_diff($msgs, $currentMessages[$category]);
+                // obsolete messages per category
                 $obsolete += array_diff($currentMessages[$category], $msgs);
             } else {
                 $new[$category] = $msgs;
             }
         }
-
+        
+        // obsolete categories
         foreach (array_diff(array_keys($currentMessages), array_keys($messages)) as $category) {
             $obsolete += $currentMessages[$category];
         }
 
         if (!$removeUnused) {
             foreach ($obsolete as $pk => $msg) {
+                // skip already marked unused
                 if (strncmp($msg, '@@', 2) === 0 && substr($msg, -2) === '@@') {
                     unset($obsolete[$pk]);
                 }
             }
-        }
-
-        $obsolete = array_keys($obsolete);
+        }        
+        
         $this->stdout('Inserting new messages...');
-        $savedFlag = false;
+        $insertCount = 0;
 
         foreach ($new as $category => $msgs) {
             foreach ($msgs as $msg) {
-                $savedFlag = true;
-                $lastPk = $db->schema->insert($sourceMessageTable, ['category' => $category, 'message' => $msg]);
-                foreach ($languages as $language) {
-                    $db->createCommand()
-                       ->insert($messageTable, ['id' => $lastPk['id'], 'language' => $language])
-                       ->execute();
-                }
+                $insertCount++;
+                $db->schema->insert($sourceMessageTable, ['category' => $category, 'message' => $msg]);
             }
         }
-
-        if (!empty($missingLanguages)) {
-            $updatedMessages = [];
-            $rows = (new Query())->select(['id', 'category', 'message'])->from($sourceMessageTable)->all($db);
-            foreach ($rows as $row) {
-                $updatedMessages[$row['category']][$row['id']] = $row['message'];
-            }
-            foreach ($updatedMessages as $category => $msgs) {
-                foreach ($msgs as $id => $msg) {
-                    $savedFlag = true;
-                    foreach ($missingLanguages as $language) {
-                        $db->createCommand()
-                            ->insert($messageTable, ['id' => $id, 'language' => $language])
-                            ->execute();
-                    }
-                }
-            }
-        }
-
-        $this->stdout($savedFlag ? "saved.\n" : "Nothing to save.\n");
+        
+        $this->stdout($insertCount ? "{$insertCount} saved.\n" : "Nothing to save.\n");
+        
         $this->stdout($removeUnused ? 'Deleting obsoleted messages...' : 'Updating obsoleted messages...');
 
         if (empty($obsolete)) {
             $this->stdout("Nothing obsoleted...skipped.\n");
-            return;
         }
 
-        if ($removeUnused) {
-            $db->createCommand()
-               ->delete($sourceMessageTable, ['in', 'id', $obsolete])
-               ->execute();
-            $this->stdout("deleted.\n");
-        } elseif ($markUnused) {
-            $rows = (new Query())
-                ->select(['id', 'message'])
-                ->from($sourceMessageTable)
-                ->where(['in', 'id', $obsolete])
-                ->all($db);
-
-            foreach ($rows as $row) {
-                $db->createCommand()->update(
-                    $sourceMessageTable,
-                    ['message' => '@@' . $row['message'] . '@@'],
-                    ['id' => $row['id']]
-                )->execute();
+        if ($obsolete) {
+            if ($removeUnused) {
+                $affected = $db->createCommand()
+                   ->delete($sourceMessageTable, ['in', 'id', array_keys($obsolete)])
+                   ->execute();
+                $this->stdout("{$affected} deleted.\n");
+            } elseif ($markUnused) {
+                $marked=0;
+                $rows = (new Query())
+                    ->select(['id', 'message'])
+                    ->from($sourceMessageTable)
+                    ->where(['in', 'id', array_keys($obsolete)])
+                    ->all($db);
+    
+                foreach ($rows as $row) {
+                    $marked++;
+                    $db->createCommand()->update(
+                        $sourceMessageTable,
+                        ['message' => '@@' . $row['message'] . '@@'],
+                        ['id' => $row['id']]
+                    )->execute();
+                }
+                $this->stdout("{$marked} updated.\n");
+            } else {
+                $this->stdout("kept untouched.\n");
             }
-            $this->stdout("updated.\n");
-        } else {
-            $this->stdout("kept untouched.\n");
         }
+        
+        // get fresh message id list
+        $freshMessagesIds = [];
+        $rows = (new Query())->select(['id'])->from($sourceMessageTable)->all($db);
+        foreach ($rows as $row) {
+            $freshMessagesIds[] = $row['id'];
+        }
+            
+        $this->stdout("Generating missing rows...");
+        $generatedMissingRows = [];
+        
+        foreach ($languages as $language) {
+          $count = 0;
+          
+          // get list of ids of translations for this language
+          $msgRowsIds = [];
+          $msgRows = (new Query())->select(['id'])->from($messageTable)->where([
+              'language'=>$language,
+          ])->all($db);
+          foreach ($msgRows as $row) {
+              $msgRowsIds[] = $row['id'];
+          }
+          
+          // insert missing
+          foreach ($freshMessagesIds as $id) {
+            if (!in_array($id, $msgRowsIds)) {
+              $db->createCommand()
+                 ->insert($messageTable, ['id' => $id, 'language' => $language])
+                 ->execute();
+              $count++;
+            }
+          }
+          if ($count) {
+            $generatedMissingRows[] = "{$count} for {$language}";
+          }
+        }
+        
+        $this->stdout($generatedMissingRows ? implode(", ", $generatedMissingRows).".\n" : "Nothing to do.\n");
+        
+        $this->stdout("Dropping unused languages...");
+        $droppedLanguages=[];
+        
+        $currentLanguages = [];
+        $rows = (new Query())->select(['language'])->from($messageTable)->groupBy('language')->all($db);
+        foreach ($rows as $row) {
+            $currentLanguages[] = $row['language'];
+        }
+        
+        foreach ($currentLanguages as $currentLanguage) {
+          if (!in_array($currentLanguage, $languages)) {
+            $deleted=$db->createCommand()->delete($messageTable, "language=:language", [
+                'language'=>$currentLanguage,
+            ])->execute();
+            $droppedLanguages[] = "removed {$deleted} rows for $currentLanguage";
+          }
+        }
+        
+        $this->stdout($droppedLanguages ? implode(", ", $droppedLanguages).".\n" : "Nothing to do.\n");
     }
 
     /**