China, the most populous country in the world, has close to one
billion people that speak Mandarin. Spanish is spoken by a less than
half that number, primarily in Mexico, Spain and the countries in South
America. English follows close behind, with Hindi in India and Arabic in
the Middle East making up the top five. Or so you would think.
The most common language in the world is actually not human at all.
In fact, it is not even spoken. Research has shown that micro-organisms
communicate with each other, and that bacteria and fungi — which far
outnumber all animals and plants on Earth, by several hundreds of orders
of magnitude — talk among themselves and to each other using
fragrances, especially terpenes.
