How to Construct a Language for Fiction

Most of what I've done in terms of language construction has been for fiction and it's been for fiction mostly read by English speakers although Shadowcent is being translated now. A project called Geograms for augmented reality mobile phone game based around Melbourne where we created a non-human language expressible but it is a set of visual symbols that capture locations around Melbourne. And then there was one test for a shadow language for Shadowcent but the um kind of evil magic people.