Divine, you have really hit the nail on the head then with your example. I have my own battle with self-image and it actually bothers me when people pay me lipservice and make a less than honest compliment.
You made me look at a different side to this thread.
If this person is concerned about their conversational skills then to them there IS a problem. I think this problem only perpetuates itself.
I suppose one way to change and gain some confidence is to study the mannerisms and speech of others and try to model their own based on observations. Another would be to pause and ask oneself if what they are about to say 'works'.
I found this website and gleened it over. I am adding the link directly to improving conversation.
Articles On How To Make Conversation