Like anything else, interpersonal skills are something you need to work on. A couple of quick suggestions that should help, although bear in mind these WILL push you outside your comfort zone. No real development wont.
OK, it's important to talk with your work colleagues, but since that's a bit scary, try practising with strangers. If you catch the bus, make a comment to someone else at the bus stop (even if it IS just about the weather to start). Standing at the supermarket waiting your turn to check out, is another opportunity. Watch the news, note something and work out a one-line comment on it - then try to find or make the opportunity to say it to someone, doesn't matter who. The more you open up with people, the easier it will get.
PS, communication doesn't always have to be words. Try just catching someone's eye, and exchanging smiles at work first. The one that smiles back the nicest will be the easiest one to approach & chat with the first time... ;-)
