While primarily for referring, non-referring information can sometimes be included in the nucleus without interfering with the referring function. For instance, we can add information to an already uniquely-referring NP, making the reference more explicit: The [granny smith] apple on the table; this [enjoyable] book. The degree to which informing and referring can be so integrated varies from domain to domain.
The major constraint we seem to face is that there is a degree of expectation under conversational implicature that the speaker refers using information known to the addressee (see Dale & Reiter 1996). Thus, in a situation where only one apple is visible, if I say pass me the Spanish apple, the addressee might be confused by the inclusion of the superfluous information, and perhaps think there must be another apple somewhere.
However, in some registers this form of reference seems to offer no problems. Appelt (1985) mentions the case of the speaker pointing at some implement and saying use the wheel-puller. The addressee, not knowing the name, but having the item identified through pointing, accepts the naming. We thus have an NP whose head-noun is not serving a referring function, but rather an informing function, since the referring function was otherwise fulfilled.
The newspaper genre is particularly strong on this type of reference, as shown by the newspaper article below:
Student fights for life after flat fire: A young student was today fighting for her life after fire ripped through her Edinburgh flat. Nicola Graham is in a ``serious but stable" condition at the specialist burns unit in St John's Hospital, Livingston. Firefighters suspect the blaze may have been started by a dropped cigarette in Miss Graham's bedroom. The 19-year-old was transferred from Edinburgh Royal Infirmary to St John's for emergency burns treatment. ..."
The sequence of references to the student successively add new information: A young student: Age and occupation; Nicola Graham: Name; Miss Graham: Marital status; the 19-year-old: Age. This writer is not depending on assimilated information to refer, but, depending on the lack of potential confusors, is successfully referring with new information. While this style is more typical of newspaper reporting, where compact information delivery is important, it is still an issue which needs to be addressed in any NP-planner.
In the register of museum object descriptions, it seems that the degree
to which new information can be included in the nucleus
is limited. New information seems not to be appropriate in the Deictic, Classifier,
Thing or Qualifier slot, but is generally allowed in the Numerative and Epithet slots.
This makes some degree of sense, since these slots are the least restrictive.
The Numerative can be used restrictively when used contrastively, e.g., the five
cups (but not the set of three), but this is rare. Epithets generally add qualitative information, and are thus less restrictive.
Another approach is to examine the semantic types of pre-modifier elements, to see which, when inserted for informing reasons, seem to interfere with the referring function. We have found some of our fact-predicates interfere more, some less. As a result of this, we maintain a list of fact-predicates which are judged, for the current domain, to be suitable for pre-modifier slots without interfering with reference. This allows us to produce, for instance, this [important] designer; the [gold and enamel] brooch designed by King; the [quite influential] Art-Deco style.