Single topic conversation and one side

Hi,

I am after some advice on how to "teach" (its the wrong word but you will get what I mean) my 17 year old son the art of conversation. I love talking to my son, he has a wicked sense of humour but I have concerns that he only has one typic of conversation, he never moves the conversation on to other topics nor is it a balance conversation (he does all the talking).

What worries me is that when he moves into the working environment etc that people will ignore him due to his conversational skills.

I have tried to say to him that when talking to others that he shouldn't always talk about things he is comfortable with etc but he seems to take offence.

Are there any tips/tricks to help when having these conversations? I want my son to be able to converse with confidence and be able to form good bonds with people.

Many thanks