Tested on 3.14.05, the JavaScript calendar aka DatePicker is not translated in circulation page for date due and renew date (you see Now, Done ...). Strange because the page calls calendar.inc which contains translated texts.
This bug was fixed by 11618 which has been pushed to master but not stable. It applies cleanly to 3.14.x. *** This bug has been marked as a duplicate of bug 11618 ***