This article investigates a particular phenomenon of coordination that delivers important clues about the nature of syntactic structures. We call this phenomenon LEFT NODE BLOCKING -the designation is a play on the related concept of RIGHT NODE RAISING. Left node blocking provides insight into how syntactic structures are produced and processed. The dependency grammar analysis of the left node blocking phenomenon put forth here focuses on ROOTS in coordinated strings. By acknowledging roots, it is possible to discern what coordination is revealing about syntactic structures. In particular, coordination delivers evidence for relatively flat structures.
THE COORDINATION DIAGNOSTICThe use of coordination as a diagnostic for constituents can be traced at least as far back as Chomsky (1957: 36), who wrote that 'the possibility of conjunction offers one of the best criteria for the initial determination of phrase structure'. Ever since then the willingness to employ coordination as a test for constituents has been unrivaled by the other diagnostics that are typically used (clefting, pseudoclefting, proform substitution, answer fragments, etc.). There is, however, a serious problem with coordination as a diagnostic for constituents: it is too liberal; it identifies too many strings as constituents, and many of these strings are not corroborated as constituents by other tests. While its liberal nature is widely acknowledged as a problem for accounts of constituent structure, the willingness to employ coordination as a diagnostic for constituents is unyielding. Most introductory textbooks on syntax and linguistics continue to use coordination as a means of demonstrating the presence of constituents in sentences. 2[1] The research presented in this article was funded by the Ministry of Education of the People's Republic of China, Grant #15YJA74001. The content has benefitted greatly from feedback provided by three anonymous Journal of Linguistics referees. For ease of reference, the main abbreviated forms that appear time and again in this article are listed here together: DG = dependency grammar, LNB = left node blocking, NCC = nonconstituent coordination, PFC = Principle of Full Clusivity, RNR = right node raising.[2] The following syntax, linguistics, and grammar books all use coordination as a diagnostic for identifying constituents: Baker