The speed of a GIF animation is controlled by the delay defined for each frame. During playback, the frame is viewed for the amount of time in its delay. Properties menu item. Then type in a new delay value in the appropriate spot in the Frame Properties dialog. Setting a delay here will set the same delay for every frame in the animation.
Preferences menu item.
Under the Defaults tab, you can set a program default for setting a delay to a new frame. This does not affect any frames already in the animation. Unfortunately the GIF file format has no provisions for including sound with an animation. The alternative of adding the sound to the Web page isn't helpful because there is no way to synchronize the animation and the sound. One possible solution is to use the AVI format since it is designed to store both animation and sound, though AVIs are not played inline like GIF animations are.