Said another way, right/left reference you, port/starboard reference the ship. Just like west is generally left on a map, but west and left are quite different.
In some cases sailing does need it's own terms for things because they precisely describe important things and concepts. In other cases, it is just a matter of history and the evolution of sailing technology. In this respect, it is no different than any other specialized field. I think that the reason sailing has a particularly rich and diverse jargon is that sailors were much more isolated than other craftsmen and specialists.
But it is (afaik) not derived from norse, norse just like dutch and german have a similar word for it. And all of thóse derive from an even older shared root, Proto-germanic
And i wrote leeway instead of leeward :/ I knew sort of but it is double hard in english