Author: Sadler, Louisa Date: April 15, 1998 Title: Syntactic Clitics, the structure-function mapping and morphological blocking Abstract: It is well known that the notions of phonological, morphological and syntactic word do not precisely coincide to pick out precisely the same elements. Such mismatches are not necessarily problematic to lexicalist theories if it can be shown that the differing definitions of wordhood are relevant to different levels of linguistic structure (thus the phonological word is not relevant to constitutent structure, but is relevant to prosodic structure). This paper focusses on a class of clitic pronouns in Welsh which appear to exhibit both properties diagnostic of syntactic wordhood and of morphological status and considers how they might be accommodated within a model which embraces the principle of lexical integrity and eschews syntactic movement. Bresnan (forthcoming) proposes a highly constrained model of constituent structure based on two (alternative) universal modes of organisation - endocentricity and lexicocentricity. For endocentric structures, a set of universal principles of structure-function association provide a canonical mapping from nodes to f-structures. This model proposes a highly constrained view of constituent structure, but does not take into account syntactic cliticisation. This paper offers an account of Welsh pronominal cliticisation within this version of Lexical Functional Grammar. We first demonstrate that the pronominals in question are indeed syntactically rather than morphologically positioned and show how the endocentric principles of Bresnan (1997) can naturally extend to these structures. The mapping to f-structure is accomodated by extending the universal principles of structure-function association to permit argument functions to be associated with clitic positions. We then turn to questions of selection and the choice between different forms of pronominal expression. Where independent pronouns compete with clitic pronouns, the latter are preferred. This parallels the competition between synthetic (inflected) and analytic (syntactic) forms which is familiar from other domains, and which is often considered to fall under some variant of a Priciple of Economy. This similarity to morphological structures might be taken as evidence that clitic-host structures are after all morphological rather than syntactic in Welsh, but we argue that this conclusion would be incorrect. Instead, we show how a natural account of this can be given within LFG by extending the domain of Andrew's Morphological Blocking Principle to syntactic clitic host structures. Note: Long version of paper presented at LFG97 San Diego.