I'm an introvert but suppose I also have social anxiety, which doesn't make me much of a talker (as much as I want to be) and it makes it hard to hold a conversation with others because I'm so self-conscious.
It's also stressful to make friends because of this, and I don't really converse with people other than those I've known before college. Whenever I do speak with new people, I feel that it's forced and insincere.
Aside from that, I'm more of a listener, but it's very difficult for me to reply with something meaningful at times. But if someone really just needs to let it all out with no judgement, I am the one to vent to.