Dinotopian dinosaurs used a simple replacement of Footprints [creating letters and punctuation] in place of the human English alphabet. The requirements to 'write' is complex 'dancing-like' moves. I would think that simple hand slashing or foot scratching/raking would produce enough simple symbols that could convey a lot of different words or ideas. I do not see the development of sentence syntax or words, but multiple symbols could produce compound words, or more complex ideas.
Are you trying to say that the "dancing" _is_ the language? Or are you hitting a pet peeve of mine by confusing a language (the thing that _has_ a syntax, words, and the like) with its writing system, as most people who talk about language do most of the time?