The Difference Between The Social Environment Of A Text And Its Context Of Situation

When we construe the social environment of a text, we are construing phenomena of first-order experience.

When we construe the 'context of situation' of a text — an instance of the culture as semiotic system — we are construing phenomena of second-order experience, that is: metaphenomena.

The cultural context is realised by the language that is projected by interlocutors.  The semiotic context realised by language is second-order experience, whereas the interlocutors doing the projecting constitute first-order experience.

See also here.