The Bribri people are an ethnic group native to Costa Rica. In the Jurassic Park films, one tribe of Bribri were the original inhabitants of Isla Nublar. The natives referred to themselves as the Tun-Si in their language. Translated into English, this was “Water Men.” Their name for Isla Nublar was Guà-Si. Translated into English, this was “Water House” or “House Beyond Water.”
The Tun-Si tribe came to inhabit Isla Nublar thousands of years ago. Their mythology was centered around Mount Sibo, named after the Bribri creator deity Sibù, because the mountain resembles the conical house. In Bribri religion, a conical house represents the universe. Tun-Si people believed that Mount Sibo was built by animals. The Tun-Si domesticated goats, but got most of their food by fishing in the oceans; unlike their mainland relatives, the Tun-Si did not believe the ocean to hold any malevolent spirits and frequently swam and fished in the sea.
Probably due to their isolation, the Tun-Si used different words and pronunciation than the Bribri people on the mainland. For example, in real life “water men” would be Wëm-Di’, not Tun-Si; “water house” would be Ù-Di’, not Guà-Si, and Sibo in real life is Sibù. However, the Tun-Si people do have some language in common with the standard Bribri language, such as “mokú-pá” as a name for the collared aracari. This translates to “parrot owl” in real life. The name of the awa, a spiritual figure in Bribri culture in real life, is also the same in the Tun-Si variant of the language.
The Spanish carrack La Estrella made landfall on Isla Nublar in 1525 under the leadership of Diego Fernández. This marked the first interaction between Tun-Si and Europeans.
After the Spanish discovered the island in 1525, the next four centuries saw the indigenous displaced from the island for various reasons.
According to Jurassic Park: The Game, InGen entered negotiations to purchase Isla Nublar from Costa Rica in 1981. The Costa Rican government enlisted a Tun-Si awa, or spiritual healer, to talk up the island so that the government could ask InGen to pay a higher price. They gave him a suit and had him cut his hair so that he would not appear simple. His daughter, Nima Cruz, and granddaughter, Atlanta Cruz, left the island with him. After his presentation, InGen purchased the island. The resettlement of the Tun-Si was planned, but delayed for several years while John Hammond toyed with the idea of building his park in San Diego. However, it was eventually moved back to Isla Nublar.
In 1987, just two years before Jurassic Park construction was due to begin, InGen began evacuating all Tun-Si off the island with the help of Oscar Morales. InGen promised that the natives would be provided with schools, homes, and medicine, but failed to deliver on these promises; as a result, most displaced Tun-Si lived in ghettos in Costa Rica. This led to former Isla Nublar inhabitant Nima Cruz to work with Lewis Dodgson to sabotage Jurassic Park, as she wanted enough money to move herself and her daughter Atlanta out of the ghetto.
At some point following the construction of Jurassic World, the native people were allowed to return to Isla Nublar under the wing of Masrani Global Corporation. Lowery Cruthers was friends with some of the natives, and lived with them rather than in the employee residence.
The Masrani corporate website gives an in-universe acknowledgement of the Bribri tribe and their contributions to the culture and history of Isla Nublar.
Article about the Bribri people on Wikipedia
Website with information on the Bribri language