I found this video about introverts to be very interesting and I thought you might, also. Many ELL's tend be introverted when they first arrive to the United States. In school they call this time "the silent period". Sometimes teachers don't understand the immense adjustment it is for a person, especially an adolescent, to perform academically, socially and culturally within an unknown paradigm. Although this video is not directly referring to second language learning, however, indirectly I think the points apply.
