IDENTIFYING AND ELABORATING THE REFERENT
The post-modifier
COMMUNICATIVE FUNCTIONS OF THE POST-MODIFIER ELEMENTS
The post-modifier elements have two basic communicative functions:
(a) to supply information enabling the hearer/reader to specify and identify the person or thing referred to by the NG, as in:
1 This is the house where the Prime Minister lives.
(b) to add supplementary information about the referent when it has already been identified, as in:
2 This is Number 10 Downing Street, where the Prime Minister lives.
These two roles or functions are encoded as defining (or restrictive) and non-defining (or non-restrictive) units, respectively. Both terms are in current use, but ‘non defining is preferred here a more transparent. In 1, the defining type, the clause where the Prime Minister lives is integrated (embedded) within the nominal group structure. Its function is to identify the house where the Prime Minister lives from all other possible houses.
When the referent is already identified or assumed to be known, as in 2, the non- defining unit is subordinate but not embedded. Its function is to add descriptive, supplementary information. Thus the same clause where the Prime Minister lives does not identify the house where the Prime Minister lives in 2, because Number 10, Downing Street is already identified or assumed to be known. Rather, it makes a linked, but separate assertion and has the status of a supplementive.
The difference between the two types of unit is marked both prosodically and in writing. Defining units such as 1 are not separated from their antecedent by either pauses or punctuation. By contrast, non-defining units are usually written between commas, dashes or brackets and pronounced between short pauses as separate information units. Punctuation is not a hundred per cent reliable, however, and it is possible that prosodic features such as pauses are not generalized either.
