I have the same experience with my DD when she was 5 months old or so. I forgot how it went away. I just let her and then after a few weeks, she did it occasionally and then I just noticed that she stopped. . . .
I can't remember all of my personality types but I am Introvert-Intuitive. I am not comfortable being the "new" person in a group of people. I freak out. I always think first before I speak and this makes people think that I am dumb or something. But I'm just processing the answer in my head before I speak.