Personally I think that it is a good thing that languages are disappearing. Imagine how easy it would be to communicate if there were only 3 or 4 world languages – Mandarin, English, French and Spanish for example. Nowadays people are considered clever if they know a major language. There are many advantages to having fewer languages in the world. Fewer languages would mean it would be easier to trade. Fewer languages would also boost national or even international unity and in turn probably sustain peace.
Many people say that the loss of some languages means that native communities disappear and with them the knowledge that could benefit humanity. I think that instead of trying to preserve the 3,500 languages under extinction we should try to distribute the knowledge from them into the wider world. After all what is the point of having knowledge of something if only a few hundred people can speak the language it is in? Especially in a world like ours where you can talk to someone in Australia in a matter of minutes, it is logical that as we become a more tightly connected world some languages should be forsaken.
In the employment realm of things it is much better for you economically and practically to know a major language, as this means you do not narrow your employment path. Also, the extinction of languages is similar to the extinction of currencies. It is so much easier to go on holiday now with the introduction of the Euro to 23 countries in Europe. Imagine having to keep changing from the German mark to the French Franc and then the Spanish Peseta. Just like currency I think it shows development if the world has fewer more widely spoken languages.