Nonviolent Communication (NVC) is a theory and practice intended to create a quality of connection among people such that they want to, and are able to, consider the needs of everyone involved in any given situation. It is also known as Compassionate Communication, because it's about learning to listen more compassionately, and to speak in ways that are likely to inspire compassion in others.
There is a large network of people sharing NVC through much of the world (see NVC people and organizations by area). In some places there are enough people supporting each other and working together that one might even call them communities.
Yet another name for NVC is giraffe Language - we use giraffe as a symbol for the kind of communication we are teaching, and jackal (or in some areas of the world wolf or snake) as a symbol for the kind of communication that is not compassionate, clear or connected.
Nonviolent Communication is also the name of a book (ISBN 1-8920-0503-4) by Marshall Rosenberg explaining the theory/practice. It has been translated into many languages.
Website for the book (with many additional materials): http://nonviolentcommunication.com/