People say that English is a universal language. While it is true that most countries in the world can speak English (mostly due in part to England's domination in the world during the colony age). However, English can be a difficult language to master, especially American English, because there are so many different words that mean similar things. Other people say that is Spanish, it is one of the easier languages to master but it remains to be one the minority languages in the world. Still others argue that in the future Chinese will be the universal language (as French was considered to be before 1800, and English is now considered). More people speak Chinese right now than anywhere else in the world (but that is because there are more Chinese in the world than any other population). Chinese, though, is one of the most difficult languages to master.
All that being said, the true universal language is music. No matter the mood that anyone is in, there is a song for it. Music brings people together better than any other form of media. Here in the United States whatever era we were in there was a musical movement surrounding it. In the 20s there was the Swing movement (a dance craze) the fully surrounded the invention of Jazz music. In the early 60s when children began questioning the authority of their parents (not nearly the first time it happened but one of the largest movements) rock had just hit the scene and helped children ponder their questions. By the late 60s as these children were hitting adulthood the protest song helped them voice their disagreement with the Vietnam Conflict.
By the time the 90s rolled around a whole new generation of children begin not only questioning the authority of their parents but their overall life. This brought us the era of grunge which completely destroyed the hit-makers of the 80s.
Around the world people still listen to and love music from the 80s (I completely understand the love for 80s music).
Everyone loves music and it does bring them together. You can go to a concert and see two people standing next to each other that have completely different political beliefs, different religious beliefs, different races, and different nationalities enjoying the artist that is up on the stage at that moment.
That is the reason that all of these music festivals have prospered as long as the have. They can bring different musicians together and people will go watch.
For instance, Bonnaroo is a music festival in Tennessee. It is entering its 10th year in existence. It originally only had bands that were considered jam bands or underground bands. As the festival's popularity has risen they have been able to bring more varied acts in.
The main line-up for this festival includes but is not limited to:
Eminem, Arcade Fire, The Black Keys, Neil Young, My Morning Jacket, Lil Wayne (who apparently is out of jail), Robert Plant, Mumford & Sons, The Strokes, Dr. John, and Alison Kraus.
It's quite a unique line-up and it is a great time. I went in 2005 and 2007.
For those that still love the hair metal days of the 80s, there is a rock festival in Oklahoma this year that brings those bands back. It is called Rocklahoma. It's line-up includes but of course is not limited to:
Motley Crue, Poison, Staind, Whitesnake, Papa Roach, Seether, Hinder, Sebastian Bach, and Black Label Society (which is fronted by the former guitarist for Ozzy Osbourne.
Music is the great unifier and the true international language.