While there were many different languages spoken within the vast Inca Empire, Quechua, specifically the "Classical Quechua" dialect, became the official language of administration, commerce, and communication throughout the empire. It was used by the Inca elite and was taught in schools.
It's important to note that:
* Quechua is not a single language but a language family with many dialects.
* Other languages were spoken within the empire. These included Aymara, Mochica, and many others.
* The Inca implemented a policy of bilingualism, where local languages were allowed to coexist alongside Quechua.
So, while Quechua was the official language of the Inca state, it wasn't the only language spoken within its borders.