This program put all the default sounds files into an assets folder. Here is how to use it.
This program requires Java 8 or higher version of Java.
First, find the index file, in my case, it would be 1.10.json
You can find the file at %appdata%/.minecraft/assets/indexes
Make sure you have run that version of Minecraft before, in this case, I would have to run 1.10 once before before being able to find the index file.
Second, execute the jar file with this command:
java -jar SoundDecrypt.jar
It will ask you to enter the index path, simply put the path and enter.
Now it will pop up a new folder called assests and there will be all the sound files and lang files in it. The folder will be located in the folder where the jar file is.
Download link: http://www.mediafire.com/file/arv7gjag831v95t/SoundDecrypt.jar
This program uses the JSON-Simple API, here is the link to the project: https://code.google.com/archive/p/json-simple/