Sl'yyth

Sl'yyth is a language used by the Lizard Folk of the world. Using a series of skin based photochemicals, pheromones and body movements to communicate without the use of sound.
Hard to categorise outside of the Lizard Folk if not impossible, no other species can seem to use it. Even Draconic species find it extremely difficult to understand it. The Lizard Folk don't care though, as it allows them to communicate silently when going about their business. It relies on body posture primarily showing basics of pleasure, pain, anger, dominance and suchlike initially. Sometimes the tail is specifically placed in certain ways to define more detail, along as frills and suchlike too, with the placement representing specific details to what they are trying to say.
Pheromones are regularly used too, giving off specific types to hint at the basic emotion behind what the Lizard Folk is trying to communicate. Anger, pleasure, sexual availability are just examples of what this is used for.
Skin based photochemicals mark a third part, and depends entirely on a number of factors. The emotions play a minor part, along with a certain mental faculty to control it to a degree, it allows for small clusters of photochemicals found around the skin to be represented. These clusters are found in the face, shoulders, upper chest, and parts of frills are common places these are found. Exactly what each one means are unknown, and can be a combination of different colours unique to the individual all the way to specific tribal groups.
Most other tribal groups can get the just of any other tribal group's communication style with the basics hardwired into them by nature. Each group will have minor differences in the colouring due to environmental factors and nearly all will have a few photochemicals that are only seen under infrared and/or ultraviolet light. Nearly all Lizard Folk can pick these up to some degree, with some better than others.

Geographical Distribution

Found throughout tropical regions by the different Lizard Folk tribes & clans. No-one else can replicate it in any shape or form.

"I knew they were talking about us in some way. Our whole party was going through the jungle looking for those serpent people, and knew the Lizard Folk had contact before with them. What we didn't know, was they were going to try to eat us, on the orders of the serpent people. Devious bunch them, kept changing patterns on their skin, and making strange facial expressions. All before jumping us. We were on edge so we got them beat back & escaped."
Aethiopean tracker talking in a Suk in Luxor.