What is the the right word?
When we talk about books and audio files to learn a new language to download what the word is right?
sources
or
resources
some people use sources and some people used resources
and what the difference between them.

Question

Answer

Sources - like the source of the Nile - is where you find the answer - I am your source for answering this question. 
resources are where you can find things to help you in your studies. Wikipedi is a major internet resource for students.
The files you are referring to would be resources for learning a language. iTalki is a resource for language learners.