I've heard recently about criticism on two performance pieces (one dance, and one theater) in which the performers chose to speak another language during part of the performance, and a viewer felt that the non-English portions took away from the piece, or that they didn't understand what was going on.
The "You're in America, speak English" complex in general is a sketchy thing, and while in some instances it is understandable that a knowledge of English is necessary, in other cases we just need to open up our minds. When critiquing artistic expression, especially with international artists, we can't look through ethnocentric eyes. Although we live locally, we have to think globally. There is much more to the world than the United States. Art, especially those art forms that are visual like dance, require you to focus on more than just words to understand. What you see and how those visions make you feel is where the understanding comes from. An artist can't feed you line by line what they want you to take away from their work. Understanding doesn't come from words alone.
Even when you speak to someone in English, you are doing more than just hearing their words to understand them. You listen to their tone, you disect their body language, and you feel their emotion. The same mechanisms of understanding should be used when viewing art with words in another language, or no words at all.