What you wrote is correct and I can not pretend, of course.
I hope that seeing the changes that I have made, you can guess if the problem is solved or not.
Thanks anyway gentle Mr. Juggledad.
Code:
function comments_number( $zero = false, $one = false, $less = false, $more = false, $deprecated = '' ) {
if ( !empty( $deprecated ) )
_deprecated_argument( __FUNCTION__, '1.3' );
$number = get_comments_number();
if ( $number > 1 && $number <12 )
$output = str_replace('§', number_format_i18n($number), ( false === $less ) ? __('§ Comments') : $less);
elseif ( $number >= 12 )
$output = str_replace('%', number_format_i18n($number), ( false === $more ) ? __('% Comments') : $more);
elseif ( $number == 0 )
$output = ( false === $zero ) ? __('No Comments') : $zero;
else // must be one
$output = ( false === $one ) ? __('1 Comment') : $one;
echo apply_filters('comments_number', $output, $number);
...and others little pieces of code.
Two of the results are these: