Читать книгу A Companion to Chomsky - Группа авторов - Страница 35

Across the history of generative grammar, the nature of phrase structure representations and how they are generated have always occupied a pivotal role (see e.g. Lasnik and Lohndal 2013). The development has gone from phrase structure rules to the X‐bar (X') schema in (26a) to the bare phrase structure representation that emerged with the Minimalist Program (Chomsky 1995), shown in (26b).

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Within X‐bar theory, the positions were fixed: A specifier is a sister to ' (read: X‐bar), and a complement is a sister to a head. In Bare Phrase Structure, all notions are relational, as can be seen in (26b) as all Xs are formally identical. The reasoning behind this shift was that phrase structure representations should not introduce anything beyond what is already in the lexicon, and bar‐levels are not in the lexicon. Therefore, a verb phrase could look as in (27).¹²

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In (27), nothing beyond the lexical items are part of the representation and whether or not they is a specifier or a complement is something that is determined relationally (Chomsky 1995).

The change from X‐bar theory to bare phrase structure was seen as a major success, yet in the past 5–10 years, Chomsky has once again pushed the research frontiers by focusing on the labels themselves and on whether or not the algorithms need to incorporate facts about endocentricity or not. In previous models, each phrase had a head, thereby deriving endocentricity. In Chomsky's recent developments, endocentricity is still important for the syntactic derivation and to the interface systems, yet endocentricity is not a fundamental property of phrase structure qua phrase structure.

In deconstructing endocentricity, Chomsky has directed attention to the role of phrase structural labels: Are they needed (cf. Collins 2002), and if they are needed, at which level of the grammar may they be needed, i.e. what role do they play in syntactic derivations? As we have seen above, in Chomsky (1995), the operation merge yielded a labeled syntactic structure. That is, merge(X,Y) yields {L, {X, Y}} where L ∈ {X, Y}.

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However, adding the label is an extra assumption, merge in its simplest form takes only two objects and puts them together: there is no labeling (Chomsky 2013, 2015, Chomsky, Gallego, and Ott 2019, Collins 2017). Thus, it should be scrutinized carefully to see whether its existence is properly motivated. Chomsky (2013) argues that the simplest merge needs to be supplemented with another operation, which he calls Label. Essentially, this provides a way in which some of the effects of labeling can be accounted for, without postulating that constituents are ever labeled. This operation locates the “structurally most prominent lexical item” within a syntactic object (Chomsky, Gallego, and Ott 2019, 247). For instance, if we have the syntactic object {H, XP}, where H is a lexical item and XP is a complex object, then H will be the most prominent lexical item. The latter follows from H carrying a feature that can be located by the search algorithm as the most prominent item, which is to say that prominence is really determined by particular features. Since the search algorithm is always looking for the closest possible target, the features of H will be more prominent than the features embedded within the XP.

Chomsky and others have developed this approach to labeling in order to account for a variety of empirical patterns, ranging from movement, constraints on movement, and also diachronic change (see van Gelderen, Chapter 13 of this volume). We cannot do justice to the rich technical details surrounding labels and labeling, except make the point that this has become a core area of current developments and that once again Chomsky has provided important contributions in shaping this research.