Free S Sound Medial Words Flashcards Worksheet PDF. Printable flashcards featuring words with the medial “S” sound can be a useful tool for improving pronunciation and vocabulary. Some of the words in this flashcards worksheet are:- Whistle, Pencil, Dresser, Dinosaur, Listen, Baseball, Muscle, Whisker, Fossil, Musical, Hospital, Crystal, Biscuit, Glasses, Newspaper, Basketball