We don’t all speak the same language because we don’t learn to speak until a couple of years after we are born – and then we acquire the language of the culture we are living in. Many of the important basic tools for developing language – such as vocal chords, hearing, and the ability to recognise patterns – are all there at birth, but others are only acquired through practise, and there are dozens of grammatical rules and thousands of words to be learned. The same is true of all other activities within human societies – we learn to be obedient and loyal, how to cajole and how to threaten, from observing others. We learn how to fit in with social institutions such as our family, our schools, our work environments and our sports clubs. All these activities and institutions still differ from culture to culture, even though the world has become more closely integrated in recent decades and cultural values and particularities are more widely shared. It is especially difficult to adopt languages from other cultures. So although the Japanese, for example, have taken on the German love of classical music and we have taken on their fascination for manga, our two countries still speak very different languages, which developed over millennia in our two separate histories. However, these days it is fairly easy to imagine that in a hyper-connected world of the future – in 150 years perhaps – there may only be a single global language.
This question was answered by Prof. Martin Haspelmath of the Department of Linguistics at the Max Planck Institute for Evolutionary Anthropology.