Whether one is in Africa, Asia, or in America, one must consider what it means to enter a foreign culture. This includes America because ultimately we are citizens of heaven (Phil. 2) and, socially, there are many subgroups in our culture we don't understand.
In a conversation recently I had with one of the world's leading missiologists, Todd Johnson, director of the Center for World Christianity, he made the point that so many people in practice ridicule the learning of another culture, whether youth culture, postmodern culture, pop culture, Arab culture, .... In short he remarked that people basically say this: "I hate your language, I hate your culture, but, by the way, do you want Jesus?" Sounds absurd because it is absurd.
Already missionaries are coming to America from around the world. Imagine if they came to us and said something like this, not wanting to understand English, or our popular culture, or our customs,....If we're honest, we'd want no part with them. We wouldn't want to be friends. How do you think others feel when WE do this?