I feel completely outclassed in social settings

I feel completely outclassed in social settings I've been going out more, hanging out for drinks or boardgames or whatever. But I just feel totally outclassed, everyone runs rings around when it comes to their ability to joke and laugh and generally "banter". I feel like I have two tones of voice; "soul suckingly serious" and "fun killing stuttering". It's so frustrating, I just want to join in and have fun but it's like I *physically* can't.