Factual error: Borat and Azmat are depicted having entered Atlanta and getting off at Martin Luther King Jr. Blvd. which runs East and West. Atlanta does not have a road named "Martin Luther King Jr. Blvd." The MLK in Atlanta is "Martin Luther King Junior Drive" (00:35:50)
Factual error: In the movie Borat is supposed to be staying at the Wellington in NY. However, when the manager comes to give him the telegram that his wife had died, the name tag says the Wingate hotel.
Chosen answer: This was the Mississippi United Pentecostal Church annual camp meeting of 2006. "The power of Jesus" compels many people to sing, dance, etc...as far as the weird language, it's known as "speaking in tongues" and is generally incoherent to the casual observer. The hands in the air is a symbol of someone literally "lifting" themselves and their hearts to Jesus in worship and prayer. It's all simply an expression of their faith and religious beliefs, nothing more.
Jazetopher