It is very important to recognice that the use of one language or the other has an enormous influence on your view of the world. The eskimo talking about snow to a hawaian mentioned above is a spectacular example, but there are many, many, more subtle ones. There are dying languages that use a hexagesimal instead of decimal system of numbers. Other languages (for example amerindian ones) have a lot of different time, or even only one. We had enormous discussions here in germany about the use of masculine and feminine forms. While in english you say "the worker" to describe a worker independent of the sex, in germany we have the form "der Arbeiter" or die Arbeiterin" depending of the person being masculine or feminine. Women`s Right activists were very angry about the form describing an indistinct person being the masculine one. They argued women were reduced to second choice by language. And they are right.

But the biggest idea transported by language is the own identity. This is the reason why so much countries tried and still try to supress minority languages. I am a great supporter of the idea that national states are no longer modern. But forcing unity is the wrong way. The Danish for example are fearing to lose their cultural identity in a united europe. They are absolutely right. Denmarks economy is completely dependent on german import. Only by giving guaranties to protect small nations from being assimilated by the bigger neighbor will they have a chance to have economical success in the future. But this includes language, too. But when a language dwindles into nothingness without being supressed, this is a sign for the completed integration. It is sad, but not neccessary bad. If you feel no longer "minoritan" but "majoritan" in the first place, there is no necessarity to speak "native" at home. Me being german in the first place, lower saxon in the second, I like our native "Niederdeutsch" very much. But there is no reason for me to speak it daily. I am not forced to preserve it in order to preserve my kinfolk`s identity.