Index: trunk/core/units/general/helpers/multilanguage.php
===================================================================
diff -u -r4017 -r4029
--- trunk/core/units/general/helpers/multilanguage.php	(.../multilanguage.php)	(revision 4017)
+++ trunk/core/units/general/helpers/multilanguage.php	(.../multilanguage.php)	(revision 4029)
@@ -185,7 +185,12 @@
 						}
 					}
 				}
-				$ret .= 'ADD COLUMN '.sprintf($field_mask, $start_index).' AFTER `'.$prev_field.'`, ';
+				
+				$field_expression = sprintf($field_mask, $start_index);
+				$ret .= 'ADD COLUMN '.$field_expression.' AFTER `'.$prev_field.'`, ';
+				
+				list($field_name, $field_params) = explode(' ', $field_expression, 2); 
+				$ret .= 'ADD INDEX (`'.$field_name.'` (5) ), ';
 				$start_index++;
 			}
 			return preg_replace('/, $/',';',$ret);