It sounds like you're also in the international keyboard mode, where the accent key places accents over vowel characters without needing to do anything special. So when you try to write "can't" the system attempts to put an accent over the 't', which obviously doesn't work.
The solution is to hit the accent key twice, and then continue typing. If this bothers you and you can't figure out how to change it in the settings, let us know and we'll reopen the bug. Thanks ** Changed in: Ubuntu Status: Unconfirmed => Rejected -- Hitting the accent key causes system beep https://launchpad.net/bugs/78187 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs