Wouldn't you have to update any index you have whenever the content changes anyway (or lazily at some point thereafter)? Updating the index should be a simple

Wouldn't you have to update any index you have whenever the content changes anyway (or lazily at some point thereafter)? Updating the index should be a simple as calculating the old metaphones, removing from the index, and then reinserting the key based on the metaphones of the new content (multi/exec would is perfect for this)