Social Language, also known as pragmatics, refers to how and why we communicate. This includes non verbal aspects of communication, such as eye contact and body language. It also includes understanding and expressing emotions, making inferences and predictions, understanding what behavior is expected in specific situations, staying on topic in conversation, negotiating, and solving problems.
This site is offering free 30-day trials and has some great materials: Everyday Speech
This page has links to videos and suggestions about how to use them: The Speech Express
Lots of great free read-alouds and videos here: Social Thinking
There's some great information and activities on this site: Do 2 Learn