"Deirdre McCloskey has estimated that around a quarter (pdf) of US GDP is talk: think of lawyers, salesmen, journalists and managers among others. The proportion is so large because communication facilitates trade, entrepreneurship and the division of labour. It's difficult to buy and sell without talking - at least if the products are complicated. The division of labour requires coordination between individuals, which requires communication. And you learn about profitable opportunities through listening and reading." from The Benefits of English. Some commenters disagree.