Underwater Sign Language
An essential part of communication with others is a function of the ability to vocalize sounds, write symbols and use body language. If physical conditions altered radically, we would be forced to adopt new techniques to break the isolation. In such a case a broad imagination could create infinite possibilities if we are able to suspend our disbelief of what can change.
Imagine waking up in a completely underwater existence while all our recollections from living on land are conscious, and we fully remember breathing and speaking. There is no memory of how we got here, nor is an explanation given for the transformation, what it means, or how it could have happened. Then, the challenge is being left alone with others in the same conditions to figure out ways to communicate with each other. Where would you begin?