Quechua is one of the three languages that Lara can learn in Shadow of the Tomb Raider. The other two are Mam and Yucatec. Like these, Quechua is a real language that is still spoken today by the Maya people of Meso-America. During the course of the game Lara is able to improve her Language Proficiency in all of these languages by finding relics and murals. Many of the inhabitants of Paititi use one of these languages when the game is set to use the Immersion Mode.
Quechua is the second language that Lara starts to learn during the story mode of the game, after Mam. The first mural using the Quechua language - called Urgu, the Scout - is located in the Peruvian Jungle where Lara find it after crash-landing there.
In Real Life
Quechua is a languages spoken in Peru, Bolivia and throughout other regions of the Andes by the native inhabitants. It is closely associated with the Inca people. By the end of the Inca empire Classic Quechua was the lingua franca of the Andes. Today it is spoken by up to 10 million people.