One of Abney’s (1987) arguments in favour of the DP-hypothesis involves the selection of nominal expressions (pronouns, nouns or noun phrases) by verbs, where verbs tend to select pronouns. Given that pronouns are said to belong in the functional category D, it follows that NPs can instead be considered as DPs, where pronouns are occasionally presented as having a null-N complement (Salzmann 2018: 6):
As D is a functional category, the determiner realises the grammatical features of D (?-features and case) which are assigned by finite (auxiliary and non-auxiliary) verbs (Radford 1999: 187).
In English nominal expressions, a determiner does not appear to occur together with another determiner, as seen in (i) and (ii):
() i. * a this pizza
ii. * the those puzzles
Abney (1987) thus suggests that determiners are the heads of their own phrasal projections outside of the NP, as opposed to occurring in the specifier position of NPs. Hence, the proposal that the ‘s-genitive in English takes the position of a determiner is some evidence given in support of the DP-hypothesis (Abney 1987: 52). Firstly, the ‘s-genitive possesses the entire possessor constituents the recipe by the chef as well as the cat sleeping over there, following any modifiers:
() i. the recipe by the chef’s instructions
ii. * the recipe’s by the chef instructions
() i. the cat sleeping over there’s toy
ii. * the cat’s sleeping over there toy
and secondly, the ‘s does not appear with other determiners:
() i. * the recipe by the chef’s the instructions
ii. * the cat sleeping over there’s a toy
This implies that not only does the ‘s-genitive behave differently to ordinary affixes (Abney 1987: 51), but that it is like determiners such as a and the (Carnie 2011: 172; Carnie 2013: 210). In addition, the ‘s-genitive always occurs in the prenominal position of the possessed noun, which further indicates that it is a determiner (Abney 1987: 52) as can be seen in () below, and more generally in ():
Conversely, if determiners are considered specifiers of NPs, x-bar theory does not offer a solution for the possessor DP to join the tree. Under the DP-hypothesis, however, it can be seen that the ‘s-genitive is the head of the DP phrase and the possessor DP fills the specifier position of the head ‘s. Since x-bar theory also expects items which are non-heads to be phrasal1, it should be noted that the possessor DP is indeed phrasal (Carnie 2013: 208, 211).
1 Although Carnie (2013) states that it is the elegance of the theory, as opposed to empirical data, that substantiates this constraint.
Furthermore, there is some evidence in freer word-order languages such as Hungarian where the possessor can appear both before and after the definite article:
() i. a Peter kalap-ja
the Peter-NOM. hat-3.SG.
ii. Peter-nek a kalap-ja
Peter-DAT. the hat-3.SG.
As can be seen in () and () above, the difference resulting from the change in position is the case of the possessor, bearing nominative case when positioned after the definite article and dative case when positioned before it (Abney 1987: 174–175). Thus, the structure of the DPs () and, consequently, () can be motivated as many languages hold two positions for subjects at the clausal level; hence, it can be claimed that the possessor moves from inside the projection of the possessed noun to SpecD1P, which is the higher specifier position of a functional head (Salzmann 2018: 9–10), giving the structure in (ii) above.
According to Carnie (2011), this can also be applied to English in terms of the structure of the ‘s-genitive after having ‘extended the notion of specifier from subjects to any element introduced by an EXTERNAL feature, including possessors in DPs’. Using (i) as an example, the external argument of the possessee NP toy is the possessor DP the cat sleeping over there. Thus, in order to fulfil the external feature of the possessee, the possessor DP first starts out in the specifier position of the possessee NP (SpecNP), subsequently moving to the specifier position of the head determiner ‘s due to case assignment2 (Carnie 2011: 175) as can be seen in ():