Quechua is the most widely spoken indigenous language family in South America, with roughly seven million speakers across the continent.
Quechua originated in the central Andes, especially in present-day Peru, and spread widely before and during the expansion of the Inca Empire. Today, Quechuan varieties are spoken in Peru, Bolivia, Ecuador, Colombia, Chile, and northwestern Argentina. The name covers a group of closely related languages and regional varieties rather than one completely uniform speech form.
Quechua remains especially important in Peru, where several varieties are widely spoken and recognized alongside Spanish. Ecuadorian Kichwa is another major Quechuan variety, while Southern Quechua is prominent in Peru and Bolivia. The language family also contributed vocabulary and place names that remain visible throughout the Andes.
A common mix-up is Guarani, which is one of South America’s most important indigenous languages and an official language of Paraguay. However, Quechua has the larger overall speaker population across South America, making it the standard answer to this question.