The English language is the overall most expressive of any language, and has the biggest vocabulary. The origins of English language come partly from Germanic or Scandinavian languages, Latin via the Romans and later Christians, Greek via Christianity and their original Celtic roots. Therefore English is a strongly composited language with great inventive flexibility. It also has a very easy grammatical structure compared to many other languages. Because of the related roots into other languages - it is also like the common denominator - being able to draw parallels into many other European languages.
I "think in English" most of the time, and have done so since being a little kid. I switch between writing in English or other languages for notes I make - sometimes I even use Portuguese.
One thing I must say is that it is very nice knowing more than one or two languages, because it makes it possible for you to listen to people without the bias of any translation - and as we know there is a lot being said using different rhythm, stress and intonation to express more than just the words.
Sure, you can live happily in a cocoon of only knowing about your own vast country, the national news and national culture. But in the end, that keeps you at a lot greater disadvantage in the global economy and communication network - like the Internet. It is actually great and refreshing to read news and opinions in other languages - insightful. It also helps in business competition - it makes it easier to connect and get along with other people. They immediately get pleasantly surprised when you know something about their language or culture. It helps you prepare for more global business.
Isolationism is not really the best path into the 21st century and the "Internet societies" that is forming. If you want to take part in the forming of the future - you have to do that on terms that are shared by more people than you and your immediate group of friends.
But sure, if you grow potatoes in Idaho - it really doesn't matter that much - and you may never have been outside your state or town...
In school (K-12) it was compulsory to learn 5 languages. I find that pretty valuable - both in terms of being able to understand linguistics and know more about the world. Just for the interest of Asian cultures I studied Japanese for 1 year at university speaking, reading and writing (with a female professor I learned to speak like Japanese females .. hehe, Japanese males speak a little different) - but I like languages and am fascinated by the structure and expressiveness/information value of languages - natural and formal.
Just my â¬0.02.
