Neprofi, till now we don't have a clear idea about what are you trying to do, i. e., what kind of app you are trying to do.
If you don't show your code, we don't know what you are trying to do.
For example, why are you wanting to reproduce the whole folder? This contradicts what you are doing till now. One could expect this from a music app, but not from an app which plays sounds of words in a foreign language and in your language. It is supposed that people should play one sound at a time and carefuly pay attention on them.