In virtue of this sovereignty over languages and letters, the free peoples must also be masters of their laws, for they impose on the laws the senses in which they constrain the powerful to observe them, even against their will.... It is naturally not in the power of monarchs to deprive the people of this sovereignty, but, in virtue of this very inalienable nature of human civil affairs, such sovereignty, inseparable from the people, contributes largely to the power of the monarchs, for they may issue their royal laws, which the nobles must accept, according to the senses that their peoples give to them.
[Giambattista Vico, The New Science of Giambattista Vico, Bergin and Fisch, trs. Cornell University Press (Ithaca, NY: 1976) p. 342 (section 936).]
This is an excellent point, and a fruitful one. It explains one of the major mechanisms by which customary law works and also why, in any society that is significantly democratic in intent, so much of politics inevitably becomes a struggle over language, as well as the point explicitly noted by Vico, why populism and monarchy tend to march together.