The "lingua franca" for doing business should be English and more companies should demand English proficiency from their employees.?

Solely depends on the location of your own business center and your customers.

Imagine a scenario where your office is in China and your customer are the local retailers there. Then English would hardly be an advantage there.There has been a little change in my mindset after I worked overseas away from my home country that "English is just another language".

I agree with your answer Mr. Nitin, thanks a lot.