Craodnada

Before the Deadlands, before Croi, before The Understate of Palme, there was Craod. The ancient country is the ancestor of both Croi and Palme.
Craodnada was the language spoken in Craod and the history of the language mirrors the history of its country. Before the Saefi War, Craod controlled the land currently controlled by Croi, as well as the deadlands when it was still normal earth. In the early history, there were not many people and governments were lax, but there was generally an area known as Craod that occupied the area. During the Saefi War, the earth was scored by the talons of an other worldly creature, or perhaps the claws of Saefi herself. From the scratches in the earth, the Deadlands spread, slowly splitting Craod. Craodians fled the area where the deadlands spread, leaving the area abandoned.
Palme itself didn't truly form until Rúna Murtas and Aisha Royle found the caves underneath the deadlands. Before that, a breakaway group of Craod citizens began distancing themselves from the country. Many of the early settlers of Palme were from these groups. The Craodana language slowly began shifting in these groups, introducing code phrases and slang that shifted the language as years slowly integrated the changes into the language.
The languages shifted more rapidly when Palme was actually established. [Croi's language] is closer to Craodnada than [palme's language], but neither is truly Craodnada any more. With the physical barrier of the Deadlands, change was rapid, especially in the Understate's small population. As the countries rapidly evolved and diverged so did their languages.
The root of [Palme and Croi languages] share enough similarities that citizens of the two countries can struggle through a conversation. Both may also read Craodnada, although this is more challenging, as both languages have modernized from the language before splitting. With enough patience, the main idea of the message may be untangled.