When people go about making their own magical “systems”, there tend to be two popular routes they take: making their own magical language or creating random sigils. The problem, though, is that those two popular methods alone technically don’t create a magical system. A magical system is a collection of classes and rules for those classes. If you were to look at classical and historical “magical systems”, you will see a formally articulated set of metaphysics and rules. This is especially clear if you look at Western occultism. The problem with creating your own magical language is that it only arbitrarily references concepts so it has the same meaning as your native language in “disordered” ways. The “words” in your language are just an arrangement of characters for the identifier for the concept. It technically doesn’t lay out any rules that allow for the formation of “magical structures”, so you can’t really build any consistent spells out of it. The same could be said for popular ways of making sigils. By crossing out letters and rearranging lines and such, you are only changing the symbol for a concept. It has the same meaning, semantically, as if you did not turn it into a sigil. To make your own magical system, you would need to make your own magical classes. The easiest route to go about doing that is to create a backbone from things called equivalence classes and relations. This article I wrote will show you how to apply thos to magic.

Make Your Own Magical Rules:
http://www.noein.co/2019/05/11/make-your-own-magical-rules/