Difficulty Socialising cause nervous

I find it difficult to socialise with people I do not know very well, such as family members, co-workers because I get too nervous and can not speak.

I sort of withdraw into myself or say really high squeaky hellos and then nothing at all. Some people have called me weird for not communicating properly....

I also find it difficult to join in when all my friends are talking together.

Do any of use experience this? How can I open up more and stop being so nervous?