You are what you speak.

I found this article in New Scientist.

The general theory with language has been that there are underlying rules; some kind of pattern which connects all languages that ever have been. This is termed "universal grammar" and was put forwards in the 60s by Noam Chomsky. However, a new theory has been presented courtsey of two guys called Evans and Levinson. Their theory is that the language we learn actually shapes our brain.

So what made linguists question the universal grammar theory?

-> It was thought that there would never have been a syllable in any language that begins with a vowel and ends in a consenant if it didn't also have syllables that begin with a consonant and end with a vowel. But this was shown to be wrong when the language Arrernte was found.

-> It was thought that every language would at least have verbs and nouns. Some, however, don't.

-> The fact that where some languages need an entire sentence to depict something, other languages have but one word for the meaning (e.g. In English, for example, you'd say "I cooked the wrong meat for them again". In the Indigenous Australian language Bininj Gun-wok you would say "abanyawoihwarrgahmarneganjginjeng"). It's hard to see an underlying structure in the two.

But there's a more worrying, or at least more eye opening, side to this discovery:

This theory suggests that humans are more diverse than we thought, with our brains having differences depending on the language environment in which we grew up. And that leads to a disturbing conclusion: every time a language becomes extinct, humanity loses an important piece of diversity.

Considering that half of world languages have gone extinct in the past 500 years, it's scary how much we must have lost with them. Each particular brain structure must have had with it new ideas that we could have used to enrich the world and improve it. With all the problems we're facing, we can't really afford to be losing out on new ideas.
Every time a book is translated, it loses some of its authenticity and some of its original meaning- hence the phrase "lost in translation". If so much can be lost simply by the act of translation, how much do we lose every time a language goes extinct?
I guess the blow is softened if the language evolves into another instead of just disappearing- which I would presume would happen because shifting language would be extremely difficult for a society (the only time I can see it working is if it is a forced change- i.e. imperialism).

On the other hand, there are cultures out there which speak the same language as another country but have different ways of life and societies- for example France and the Republic of Congo which both speak French. On the other hand, there are other recognised languages in the Congo- it's just that France is the official national one.

Also, presuming all of this is true, the evolution of new languages will mean new cultures and new ways of life which is exciting.