How To Distinguish Non-Defining From Defining Relative Clauses — From Below

In terms of how they are typically realised phonologically:

• a non-defining (ranking) relative clause and the clause it hypotactically elaborates are each 'realised by a tone group, and each tone group selects the same tone' (Halliday & Matthiessen 2004: 396), whereas

• a defining (embedded) relative clause does not 'form a separate tone group' (op cit: 429).