Being a new Ubuntu user, I've no idea where to begin to solve this problem.
I installed Ubuntu into WinXP with Wubi. Tried downloading Minecraft and installing Sun Java, and everything worked well.
Then I played around to get Adobe Flash to work correctly, installed some sound packages and some non-free extras thing, I don't recall everything I did. Tried to get some speech synthesis applications to work. Suddenly I noticed I had two java versions installed, but I (think I) managed to get Minecraft to load with the the Sun version, by selecting "Open with" etc.
However, I am stuck with Minecraft sound being laggy. Sound plays 4-5 seconds after the action, and not all sounds play. E.g. if I whack something 10 times, 1 sound plays.
Also, eSpeak no longer works.
espeak "Hello" is completely silent.
I think something is messed up with my sound, but I have no idea where to begin to solve this. Any advice would be appreciated.