How to define custom date format in page.tpl.php?
You are right using the correct API format_date(). What you need to do is passing correct value to it.

&lt;?php print format_date(time(), 'short'); ?&gt;


According to the API doc, the function signature is:

format_date($timestamp, $type = 'medium', $format = '', $timezone = NULL, $langcode = NULL)


And it explained how you should handle the translation.


  $langcode: (optional) Language code to translate to. Defaults to the language used to display the page.


$langcode is handled automatically if you keep it as default value.