An alphabet with seven orders of change. One method is to begin each word or distinct thought with the next order. This could be done with an existing alphabet, but I imagine one with seven symbol sets. For example, an alphabet where 1/7th of each character disappears with each new order, or a liquid alphabet where a new instance of the protoform emerges at each order. A short example of doing it using a ‘sliding starting letter’ in English follows:

A wise tale is a good guide.

0 1 2 3 4 5 6
A xjtf vcng lv e lqqi maojk.