Personalized Keep Calm Polka Youth Long Sleeve T-Shirt. Funny novelty Polish music, German music, polka music, accordion lovers, polka band Youth Long Sleeve T-Shirt - White with accordion graphic says KEEP CALM POLKA ON. Gifts for polka lovers, oompahpah, squeezebox players, polka bands and festivals. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)