Actually…there is another way to do this and it doesn’t need the messing about with the URL.
What appears to happen is that the “unique id” of a page with a thing passed to it in a “pretty” format is preserved in the unique id.
So…
Here is a page that takes the data type “Word”. Word Up.
The Page is “slugtest” and we are passing “Shorterword” in as a parameter.
Pass in whatever you like after the page name, and it appears in the “unique id” as is.
Then just look that Unique Id up on something and you have your pretty/semantic/permalink.