How is it that there are semiological systems? How many are there? Are they always the same systems or different systems? And if different, in what way? Is there a relation amongst them?
Benveniste identifies the foundational questions Saussure left unanswered, establishing that a genuine semiology must theorise the plurality of sign-systems and the relations among them.
, Last Lectures: Collège de France 1968 and 1969, 2012thesis