Do Bladesingers actually sing when they perform bladesong?

@mikemearls Do Bladesingers actually sing/dance when they perform bladesong? Does that prevent stealth if using it? Does silence end it?

— QuantumCat (@TheQuantumCat) December 28, 2015

I believe rules are silent on this, but I'd allow stealth. Picturing slow, tip-toe/ballet steps in my mind. https://t.co/gMFuwJmTp9

— Mike Mearls (@mikemearls) December 28, 2015