If the earth is spinning at 1000 miles an hour and sound travels at 767 miles per hour, how can we hear anything?

You, the earth (including earth’s atmosphere), and the thing making noise are basically a closed system. In other words, all these items feel forces together. In this case since you are all moving at a 1,000 mph your perception is that you aren’t moving.

In the case of sound, it is simply moving through that medium, the earth’s atmosphere, at 700 mph.