A technical objection arises if assignment demands independent signification, while a particle’s full interpretation depends on other elements. Does that make particles fall outside the definition of assignment?
Consider “fī” and “min.” Their general relational functions are conventional, but identifying what is in what, or what begins from where, requires a broader expression. Some classical approaches therefore treat the assignment of particles differently from that of nouns and verbs.
The countervailing approach treats the general relational signification itself as conventionally assigned, even though each specific relation needs contextual completion. The debate turns on what is meant by independence in signification.