The Fleurian Language of Secrets

The Fleurian language of secrets is unusual for many reasons. Its origins, forms, development and eventual decease as a language all combine to set it apart.
Origins
The now defunct Kingdom of Fleurice was formed by elves emigrating from the Barsian Empire, disdaining the established colonial state of Aeltice, and settling themselves in the territories further west, occupied mainly by the human tribes of the Galay people. As such, they established themselves as a ruling nobility above native peasantry, set apart further speaking by the ancient elven language of Barsalf, unknown to the native Galay.
The creation of the language at this time was therefore neither a natural linguistic evolution, nor a political or scientific invention. In fact, it was a social one, as it began as a form of flirtation among the nobility. Certain coy gestures with fans, gloves, or other fashionable accessories moved from indicating interest, to being used as coded signals to arrange assignations. But this was still only the beginning of its evolution as a language.
Development
Although the Language of Secrets developed intricacies over time, it was still focused on the same type of social interactions, and distinctive in its use of particular objects, which made it vulnerable. Over time, observant watchers could easily identify that some form of communication was taking place, even though they may not be able to interpret the details of a message.
However, as civil unrest grew, the politically savvy elven spymasters took the framework of the language of flirtation, and developed it in new ways, enabling them to pass more detailed, complex and vital messages in secretive and subtle ways.
Forms
At the height of its development, this rich and complex language had an amazing versatililty, enabling thousands of specific meanings to be conveyed. However, to provide a brief summary, some of the key features are described here.
Motion: As a gestural sign language, various movements can be used to indicate a change, or the passage of time or distance. Speed of motion can also be used to indicate intensity, and direction to show how one thought or concept relates to another.
Position: The positioning of any gesture or sign can be used to indicate what the general topic of conversation may be, thereby changing the implications of various signs in context.
Indicating object: Objects can be used to add other contexual information, either as an indicator of a particular topic, or by the type of object used. For example, what originated as simple messages conveyed by tapping a closed fan against a cheek, or a shoulder, became a whole range of communications to be used with any rigid stick-like object, such as a pen, or a nail. The choice of a particular object may be as simple as something inconspicuous in the setting where the message is being conveyed, but may also indicate something about the message itself.   Similarly, signals originating in the handling of gloves could be recreated with any flexible material, opening up a series of draping, wrapping, or twisting actions, each of which may have their own significance.
Demise
The end of the language, as with much of the culture developed by the Kingdom of Fleurice, came with the advent of the Galiate Revolution, overthrowing the Kingdom and establishing the modern Gallate Republic. At this point, the coding of the language was being broken, and messages intercepted, which in itself might have indicated the end of the usefulness of the language.
However, as with its origins, the end of the Fleurian Language of Secrets is also intricately connected with the social environment around it. Ultimately, with the change in power after the Galiate Revolution, the language became a symbol of the decadent society that had been replaced, and knowing it well enough to use it became something that would attract suspicion and mistrust.