I think extroverted learner and introverted learner are an important role that influences the learning of second language. For example, students who are easy-going and self-confident are fearless when they communicate with foreign teacher and including other foreigners. They will not worry about the mistake when they speak wrong and at the same time, they always ready to learn and solve that they wrong. We can see that extroverted person will make faster progress in learning of second language. Every day they try to improve self, practice over and over again and their English language skill are constantly improving. It makes them feel enthusiastic all the time.
On the other hand, I think introverted leaner will make slower progress. They do not like to speak or interact with foreigners. When they have to talk with foreign teacher, they are under the pressure of their speaking, pronunciation, structure of sentence or grammar of sentence. So; from those reason, it makes them do not like to meet foreigners. Anxious learners always worry about mistake that can happen when they talk with foreigners. It makes them not have an opportunity to communicate with foreigners. Therefore, they will learn second language less than learner who extroverted learner certainly.