One thing that jumps out at me is that you have no breaks in your cases, so it will fall through, execute all the cases starting with the first match, and finally execute the default case, no matter what you enter.
You are missing break statement in each case of your switch. Check the tutorial:
The break statements are necessary because without them, statements in switch blocks fall through: All statements after the matching case label are executed in sequence, regardless of the expression of subsequent case labels, until a break statement is encountered.
The quieter you are, the more you are able to hear.
If it's E, it will execute E, D, C, B, A, but not default. If it's B, it will execute B, A, but not default. And so on. If it's none of those letters, it will execute default.
I believe you're allowed to put a break at the end of the default case as well (though it may generate a compiler warning), but it's not necessary. What matters is that you have one right before the default case.