According to the Swedish linguist Mikael Parkvall: ‘Languages are very unevenly distributed among the countries of the world.’ He lists the world’s countries with the largest number of languages:
Papua New Guinea 
DR Congo 
United States 
It’s curious how the linguistically most diverse country in the world is Papua New Guinea – because it’s also the place with the biggest biodiversity anywhere, one of the last places in the world where new species get discovered regularly. It leads one to wonder whether there could there be a single explanation for both phenomena?