Well, I would use a counter to add a delay between each footstep. If the counter is zero, play the sound and put the counter up to some fixed value (smaller value if running, or something like that). Here's pseudo-code, which assumes the character is moving:
if counter = 0 then play sound and set counter to 20,
if counter > 0 then subtract one from counter.
This will repeat the footstep sound every twenty frames. This should be about right for a light jog on a game running at 30fps; however, you'll probably need to tweak it to get the best result. Does this help?
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