Assuming it is only a sound problem re YouTube, the App may have been corrupted in some way. Double click on the home button when a row of icons that you have been using will appear on the bottom row. Press and hold any icon until it jiggles and a minus sign appears on the icons. Choose the YouTube icon and tap the minus sign to remove it.
This will not remove the icon from the iPad but will tidy it up. Go back to the home screen and start the YouTube icon again. Let us know if that works as it can help others. If no good other suggestions are available.
Hey, welcome to the forum!
Regards, Andrewddc28
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