Most words that give students trouble will have an audio clip button to indicate that you can click on it to download an audio clip to hear the pronunciation.
Other Notes on Sound:
A sound playing application is built into Netscape, so try the wave (.wav) format first. The .aiff format is generally for Macintoshes equipped with SoundMachine.If you have SoundApp installed and configured to play wave files, the file will load and automatically play for you. If you have another sound player installed (or the sound player that comes with Netscape) you MIGHT HAVE TO CLICK ON THE PLAY BUTTON TO HEAR THE SOUND FILE.
It can be an annoyance to have to wait for the sound file, and then hit play -- it may be worth your time to set up SoundApp. You'll only have to this once.
In addition, PCs must have a soundcard and be configured properly for sound. (For more details on how to configure your PC for sound, see the section Configuring Your Computer for Sound, or the FAQ section "Why won't the audio clips work?"