diff --git a/admin/themes/default/template/cat_modify.tpl b/admin/themes/default/template/cat_modify.tpl
index 348683003..0a1b7f700 100644
--- a/admin/themes/default/template/cat_modify.tpl
+++ b/admin/themes/default/template/cat_modify.tpl
@@ -14,7 +14,7 @@
   {/if}
   {if isset($U_MANAGE_ELEMENTS) }
   <li><a href="{$U_MANAGE_ELEMENTS}" title="{'elements'|@translate}"><img src="{$ROOT_URL}{$themeconf.admin_icon_dir}/category_elements.png" class="button" alt="{'elements'|@translate}"></a></li>
-  <li><a href="{$U_MANAGE_RANKS}" title="{'ranks'|@translate}"><img src="{$ROOT_URL}{$themeconf.admin_icon_dir}/ranks.png" class="button" alt="{'ranks'|@translate}"></a></li>
+  <li><a href="{$U_MANAGE_RANKS}" title="{'manage image ranks'|@translate}"><img src="{$ROOT_URL}{$themeconf.admin_icon_dir}/ranks.png" class="button" alt="{'ranks'|@translate}"></a></li>
   {/if}
   <li><a href="{$U_CHILDREN}" title="{'sub-categories'|@translate}"><img src="{$ROOT_URL}{$themeconf.admin_icon_dir}/category_children.png" class="button" alt="{'sub-categories'|@translate}"></a></li>
   {if isset($U_MANAGE_PERMISSIONS) }
diff --git a/admin/themes/default/template/upgrade.tpl b/admin/themes/default/template/upgrade.tpl
index 26274ec76..4b1964775 100644
--- a/admin/themes/default/template/upgrade.tpl
+++ b/admin/themes/default/template/upgrade.tpl
@@ -124,7 +124,7 @@ textarea { margin-left: 20px; }
 {/if}
 
 {if isset($upgrade)}
-<h2>{'Upgrade from %s to %s'|@translate|@sprintf:$upgrade.VERSION:$RELEASE}</h2>
+<h2>{'Upgrade from version %s to %s'|@translate|@sprintf:$upgrade.VERSION:$RELEASE}</h2>
 
 <p><b>{'Statistics'|@translate}</b></p>
 <ul>
diff --git a/feed.php b/feed.php
index d162fadfa..cfebc8352 100644
--- a/feed.php
+++ b/feed.php
@@ -80,7 +80,7 @@ SELECT user_id,
   $feed_row = pwg_db_fetch_assoc(pwg_query($query));
   if ( empty($feed_row) )
   {
-    page_not_found('Unknown/missing feed identifier');
+    page_not_found(l10n('Unknown feed identifier'));
   }
   if ($feed_row['user_id']!=$user['id'])
   { // new user
diff --git a/language/en_UK/admin.lang.php b/language/en_UK/admin.lang.php
index 45e351444..0dbe00d8a 100644
--- a/language/en_UK/admin.lang.php
+++ b/language/en_UK/admin.lang.php
@@ -126,7 +126,6 @@ $lang['Name'] = "Name";
 $lang['New name'] = "New name";
 $lang['New parent category'] = "New parent category";
 $lang['New tag'] = "New tag";
-$lang['No tag defined. Use Administration>Pictures>Tags'] = "No tag defined. Use Administration>Pictures>Tags";
 $lang['Number of comments per page'] = "Number of comments per page";
 $lang['Number of rates'] = "Number of rates";
 $lang['Number of thumbnails to create'] = "Number of thumbnails to create";
@@ -335,7 +334,6 @@ $lang['Send mail on HTML format'] = "Send mail in HTML format";
 $lang['Include display of recent pictures group by dates'] = "Include display of recent pictures grouped by dates";
 $lang['Available only with HTML format'] = "Available only with HTML format";
 $lang['no write access'] = "no write access";
-$lang['path'] = "path";
 $lang['Permissions'] = "Permissions";
 $lang['private'] = "private";
 $lang['Properties'] = "Properties";
@@ -354,7 +352,6 @@ $lang['A local listing.xml file has been found for'] = "A local listing.xml file
 $lang['read local listing.xml and update'] = "read local listing.xml and update";
 $lang['test'] = "test";
 $lang['test this remote site'] = "test this remote site";
-$lang['Remote site url must start by http or https and must only contain characters among "/", "a-zA-Z0-9", "-" or "_"'] = "Remote site url must start by http or https and must only contain characters among \"/\", \"a-zA-Z0-9\", \"-\" or \"_\"";
 $lang['remove tags'] = "remove tags";
 $lang['Repair and optimize database'] = "Repair and optimize database";
 $lang['selection'] = "selection";
@@ -670,7 +667,6 @@ $lang['Forbid this theme to users'] = "Forbid this theme to users";
 $lang['Set as default theme for unregistered and new users'] = "Set as default theme for unregistered and new users";
 $lang['unknown'] = 'unknown';
 
-$lang['Upload Form'] = 'Upload Form';
 $lang['Upload Photos'] = 'Upload Photos';
 $lang['Drop into category'] = 'Drop into category';
 $lang['+ Add an upload box'] = '+ Add an upload box';
diff --git a/language/en_UK/common.lang.php b/language/en_UK/common.lang.php
index bf2f4d9ab..8f54168ed 100644
--- a/language/en_UK/common.lang.php
+++ b/language/en_UK/common.lang.php
@@ -145,7 +145,6 @@ $lang['caddie'] = "Caddie";
 $lang['Calendar'] = "Calendar";
 $lang['All'] = "All";
 $lang['display each day with pictures, month per month'] = "display each day with pictures, month per month";
-$lang['display pictures added on'] = "display pictures added on";
 $lang['View'] = "View";
 $lang['chronology_monthly_calendar'] = "Monthly calendar";
 $lang['chronology_monthly_list'] = "Monthly list";
@@ -311,7 +310,6 @@ $lang['can\'t upload the picture on the server'] = "the picture cannot be upload
 $lang['the username must be given'] = "the username is required";
 $lang['A picture\'s name already used'] = "this picture name is already used";
 $lang['You must choose a picture fileformat for the image'] = "You must choose a picture fileformat for the image";
-$lang['You can\'t upload pictures in this category'] = "You cannot upload pictures in this category";
 $lang['Name of the picture'] = "Picture name";
 $lang['Upload a picture'] = "Upload a picture";
 $lang['Picture uploaded with success, an administrator will validate it as soon as possible'] = "Picture uploaded with success, an administrator will validate it as soon as possible";
@@ -324,7 +322,6 @@ $lang['Browser: %s'] = "Browser: %s";
 $lang['Author: %s'] = "Author: %s";
 $lang['Comment: %s'] = "Comment: %s";
 $lang['Delete: %s'] = "Delete: %s";
-$lang['Validate: %s'] = "Validate: %s";
 $lang['Comment by %s'] = "Comment by %s";
 $lang['User: %s'] = "User: %s";
 $lang['Email: %s'] = "Email: %s";
diff --git a/language/en_UK/install.lang.php b/language/en_UK/install.lang.php
index d9134d8a5..a3e4f4a31 100644
--- a/language/en_UK/install.lang.php
+++ b/language/en_UK/install.lang.php
@@ -36,7 +36,6 @@ $lang['Parameters are correct'] = "Parameters are correct";
 $lang['Connection to server succeed, but it was impossible to connect to database'] = "Connection to server successful, but the connection to the database is impossible";
 $lang['Can\'t connect to server'] = "Cannot connect to server";
 $lang['The next step of the installation is now possible'] = "The next step of the installation is now possible";
-$lang['next step'] = "next step";
 $lang['Copy the text in pink between hyphens and paste it into the file "local/config/database.inc.php"(Warning : database.inc.php must only contain what is in pink, no line return or space character)'] = "Copy the text in pink between hyphens and paste it into the file \"local/config/database.inc.php\". (Warning: database.inc.php must only contain the pink text, without additional line return or space character)";
 $lang['Database type'] = "Database type";
 $lang['The type of database your piwigo data will be store in'] = "The type of database your Piwigo data will be store in";
diff --git a/themes/default/template/index.tpl b/themes/default/template/index.tpl
index 6bad8e319..522113bc7 100644
--- a/themes/default/template/index.tpl
+++ b/themes/default/template/index.tpl
@@ -19,7 +19,7 @@
       {/if}
 
       {if isset($U_CADDIE) }
-      <li><a href="{$U_CADDIE}" title="{'caddie'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/caddie_add.png" class="button" alt="{'caddie'|@translate}"></a></li>
+      <li><a href="{$U_CADDIE}" title="{'add to caddie'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/caddie_add.png" class="button" alt="{'caddie'|@translate}"></a></li>
       {/if}
 
       {if isset($U_EDIT) }
diff --git a/themes/default/template/menubar_identification.tpl b/themes/default/template/menubar_identification.tpl
index 2717e1019..703d6c87a 100644
--- a/themes/default/template/menubar_identification.tpl
+++ b/themes/default/template/menubar_identification.tpl
@@ -6,7 +6,7 @@
 
 	<ul>
 	{if isset($U_REGISTER)}
-	<li><a href="{$U_REGISTER}" title="{'Register'|@translate}" rel="nofollow">{'Register'|@translate}</a></li>
+	<li><a href="{$U_REGISTER}" title="{'Create a new account'|@translate}" rel="nofollow">{'Register'|@translate}</a></li>
 	{/if}
 
 	{if isset($U_LOGIN)}
@@ -18,11 +18,11 @@
 	{/if}
 
 	{if isset($U_PROFILE)}
-	<li><a href="{$U_PROFILE}" title="{'Customize'|@translate}">{'Customize'|@translate}</a></li>
+	<li><a href="{$U_PROFILE}" title="{'customize the appareance of the gallery'|@translate}">{'Customize'|@translate}</a></li>
 	{/if}
 
 	{if isset($U_ADMIN)}
-	<li><a href="{$U_ADMIN}" title="{'Administration'|@translate}">{'Administration'|@translate}</a></li>
+	<li><a href="{$U_ADMIN}" title="{'available for administrators only'|@translate}">{'Administration'|@translate}</a></li>
 	{/if}
 	</ul>
 
@@ -52,7 +52,7 @@
 	<ul class="actions">
 		<li><a href="{$U_LOST_PASSWORD}" title="{'Forgot your password?'|@translate}" rel="nofollow"><img src="{$ROOT_URL}{$themeconf.icon_dir}/lost_password.png" class="button" alt="{'Forgot your password?'|@translate}"></a></li>
 		{if isset($U_REGISTER)}
-		<li><a href="{$U_REGISTER}" title="{'Register'|@translate}" rel="nofollow"><img src="{$ROOT_URL}{$themeconf.icon_dir}/register.png" class="button" alt="{'Register'|@translate}"></a></li>
+		<li><a href="{$U_REGISTER}" title="{'Create a new account'|@translate}" rel="nofollow"><img src="{$ROOT_URL}{$themeconf.icon_dir}/register.png" class="button" alt="{'Register'|@translate}"></a></li>
 		{/if}
 	</ul>
 	</div>
diff --git a/themes/default/template/picture.tpl b/themes/default/template/picture.tpl
index 9ac9b430b..29421e344 100644
--- a/themes/default/template/picture.tpl
+++ b/themes/default/template/picture.tpl
@@ -49,14 +49,14 @@
       <a href="{$U_METADATA}" title="{'Show file metadata'|@translate}" rel="nofollow"><img src="{$ROOT_URL}{$themeconf.icon_dir}/metadata.png" class="button" alt="metadata"></a>
     {/if}
     {if isset($current.U_DOWNLOAD) }
-      <a href="{$current.U_DOWNLOAD}" title="{'download'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/save.png" class="button" alt="{'download'|@translate}"></a>
+      <a href="{$current.U_DOWNLOAD}" title="{'download this file'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/save.png" class="button" alt="{'download'|@translate}"></a>
     {/if}
     {if isset($PLUGIN_PICTURE_ACTIONS)}{$PLUGIN_PICTURE_ACTIONS}{/if}
     {if isset($favorite) }
       <a href="{$favorite.U_FAVORITE}" title="{$favorite.FAVORITE_HINT}"><img src="{$favorite.FAVORITE_IMG}" class="button" alt="favorite" title="{$favorite.FAVORITE_HINT}"></a>
     {/if}
     {if !empty($U_SET_AS_REPRESENTATIVE) }
-      <a href="{$U_SET_AS_REPRESENTATIVE}" title="{'representative'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/representative.png" class="button" alt="{'representative'|@translate}"></a>
+      <a href="{$U_SET_AS_REPRESENTATIVE}" title="{'set as category representative'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/representative.png" class="button" alt="{'representative'|@translate}"></a>
     {/if}
     {if isset($U_ADMIN) }
       <a href="{$U_ADMIN}" title="{'edit'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/preferences.png" class="button" alt="{'edit'|@translate}"></a>
@@ -78,7 +78,7 @@ y.callService(
   );
 }{/literal}
 </script>
-      <a href="{$U_CADDIE}" onclick="addToCadie(this, '{$ROOT_URL|@escape:'javascript'}', {$current.id}); return false;" title="{'caddie'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/caddie_add.png" class="button" alt="{'caddie'|@translate}"></a>
+      <a href="{$U_CADDIE}" onclick="addToCadie(this, '{$ROOT_URL|@escape:'javascript'}', {$current.id}); return false;" title="{'add to caddie'|@translate}"><img src="{$ROOT_URL}{$themeconf.icon_dir}/caddie_add.png" class="button" alt="{'caddie'|@translate}"></a>
     {/if}{*caddie management END*}
   </div>
   {include file='picture_nav_buttons.tpl'|@get_extent:'picture_nav_buttons'}
diff --git a/themes/default/template/tags.tpl b/themes/default/template/tags.tpl
index 4f5cd0c6d..db848cf15 100644
--- a/themes/default/template/tags.tpl
+++ b/themes/default/template/tags.tpl
@@ -3,11 +3,11 @@
 	<div class="titrePage">
 		<ul class="categoryActions">
 		{if $display_mode == 'letters'}
-			<li><a href="{$U_CLOUD}" title="{'cloud'|@translate}" rel="nofollow"><img src="{$themeconf.icon_dir}/tag_cloud.png" class="button" alt="{'cloud'|@translate}"></a></li>
+			<li><a href="{$U_CLOUD}" title="{'show tag cloud'|@translate}" rel="nofollow"><img src="{$themeconf.icon_dir}/tag_cloud.png" class="button" alt="{'cloud'|@translate}"></a></li>
 		{/if}
 
 		{if $display_mode == 'cloud'}
-			<li><a href="{$U_LETTERS}" title="{'letters'|@translate}" rel="nofollow"><img src="{$themeconf.icon_dir}/tag_letters.png" class="button" alt="{'letters'|@translate}"></a></li>
+			<li><a href="{$U_LETTERS}" title="{'group by letters'|@translate}" rel="nofollow"><img src="{$themeconf.icon_dir}/tag_letters.png" class="button" alt="{'letters'|@translate}"></a></li>
 		{/if}
 
 			<li><a href="{$U_HOME}" title="{'Home'|@translate}"><img src="{$themeconf.icon_dir}/home.png" class="button" alt="{'Home'|@translate}"></a></li>
diff --git a/tools/convert_language_to_2.1.pl b/tools/convert_language_to_2.1.pl
index fd3a5b110..535fec217 100644
--- a/tools/convert_language_to_2.1.pl
+++ b/tools/convert_language_to_2.1.pl
@@ -42,10 +42,19 @@ my %ignore_keys = (
 );
 
 my %remove_keys = (
+    common => {
+        'You can\'t upload pictures in this category' => '',
+        'display pictures added on' => '',
+    },
     admin => {
         'nbm_content_goto_2' => '',
         'nbm_content_hello_2' => '',
         'nbm_redirect_msg' => '',
+
+        'username' => '',
+        'No tag defined. Use Administration>Pictures>Tags' => '',
+        'Remote site url must start by http or https and must only contain characters among "/", "a-zA-Z0-9", "-" or "_"' => '',
+        'path' => '',
     },
     upgrade => {
         'Are you sure?' => '',
diff --git a/tools/missing_keys.pl b/tools/missing_keys.pl
index 99f929688..88c8bdc2f 100644
--- a/tools/missing_keys.pl
+++ b/tools/missing_keys.pl
@@ -57,6 +57,12 @@ my %ignore_keys = (
     'chronology_monthly_calendar' => '',
     'chronology_monthly_list' => '',
     'chronology_weekly_list' => '',
+    'public' => '',
+    'private' => '',
+    'none' => '',
+    'other' => '',
+    'high' => '',
+    'Waiting page: %s' => '',
 );