The term 'SPEAKS LIKE DAFFY DUCK' can be summarized by the crossword solution 'LISPS', which is a five-letter word. LISPS is a speech disorder in which the speaker produces sounds with an abnormal hissing or whistling quality due to the incorrect formation of certain speech sounds. This disorder is often associated with the character Daffy Duck from the Looney Tunes cartoons, who famously spoke with a lisp.