(5) clause = π4 Ei,: [[ proposition ] (σ4)n ] (Ei) The “clause” consists of an illocutionary act variable Ei, symbolizing the speech act expressed by the clause, specified by the proposition, illocutionary operators π4 and illocutionary (Level-4) satellites σ4. Level-4 elements serve to specify (or modify) the illocutionary force with which the proposition is presented.
- Dik (1989), Pag. 248

Any natural language text can be exhaustively divide into “clause” and “extra-clausal constituents”. By “clauses” I mean the main and subordinate clauses of traditional grammar. “Extra-clausal constituents” are constituents which are neither clauses nor parts of clauses. In a construction such as: (1) ‘Well John’, I believe that your time is up The constituents “well” (an “Initiator”) and “John” (an “Address” or “Vocative”) are extra-clausal constituents; “I believe that your time is up” is a main clause; and “that your time is up” is a subordinate clause.
- Dik (1989), Pag. 45