I'm always getting the message "Pay attention to accents." Only because it wasn't taught in any of the previous lessons. Duolingo should provide a stand-alone lesson that focuses on/teaches “accents,” instead of introducing it in bits and pieces in various lessons along the way.
Perhaps DL should introduce a "strict" option, where the words you type have to be perfect (no typos, with accents, ...). I find myself being rather lazy and not typing the accents.