Halliday & Matthiessen (2014: 369):
It should be pointed out here that there are two different systems of number in the English nominal group, one associated with each of the two kinds of Deictics.
- (i) With specific Deictics, the number system is ‘non-plural/plural’; mass nouns are grouped together with singular, in a category of ‘non-plural’. So this, that go with non-plural (singular or mass), these, those with plural, as in Table 6-5.
- (ii) With non-specific Deictics, the system is ‘singular/non-singular’; mass nouns are grouped together with plural, in a category of non-singular. So a, an goes with singular, weak some with non-singular (mass or plural), as in Table 6-6.