You can't. The internal storage is not accessble.
You must copy it to a temporary file.
Thks,hm,......
As i say: if i try with your sample ExternalStorage, then i can acces the file.
And, i can load file to InternalStorage. I can see this file, and folder Sounds, on my tablet with MyFiles and Total Commander.
And, also, when i connect tablet with PC, i can save files to this folder.
Also can i load and play, if the file is copied to temp. With your sample.
But, sory, i can't resolve, how to access this folder and file from my App.
I added 3 screen shots so you can see that I sent 2 files and 1 Folder to File.DirInternal.
And, once, with your App I can reach these files and folders.