Please refer to Using Silence in Asana Practice, where I opine that yoga sessions work best in silence, with occasional departures.
This may not seem important if yoga is being approached more like traditional western exercise that thinks of body as a piece of machinery operating independently from spirit, In this case we might read the paper, chew gum, have a conversation and listen to Marylyn Manson all at the same time as working the step master. But if we are pursuing yoga as in “union”, synchronizing body heart and mind in a focused present moment, a reduction not distractions that bring our attention out to multiple directions seems to make sense.