--- a/tools/letter.pl
+++ a/tools/letter.pl
@@ -290,10 +290,10 @@ sub add_validate {
my @content = $input->multi_param('content');
my @lang = $input->multi_param('lang');
for my $mtt ( @mtt ) {
- my $is_html = $input->param("is_html_$mtt");
+ my $lang = shift @lang;
+ my $is_html = $input->param("is_html_$mtt\_$lang");
my $title = shift @title;
my $content = shift @content;
- my $lang = shift @lang;
my $letter = C4::Letters::getletter( $oldmodule, $code, $branchcode, $mtt, $lang );
# getletter can return the default letter even if we pass a branchcode
--