focusing primarily on swedish, a germanic language whose particles have not previously been studied extensively, non-projecting words: a case study on swedish particles develops a theory of non-projecting words in which particles are morphologically independent words that do not project phrases. particles have long constituted a puzzle for germanic syntax, as they exhibit properties of both morphological and syntactic constructs. although non-projecting words have appeared in the literature before, it has gone largely unnoticed that such structures violate the basic tenets of x-bar theory. this work identifies these violations and develops a formally explicit revision of x-bar theory that can accommodate the requisite weak projections. the resulting theory, stated in terms of lexical-functional grammar, also yields a novel classification of clitics, and it sheds new light on a range of recent theoretical proposals, including economy, multi-word constructions, and the primitives of lexical semantics. at an abstract level, we see that the modular, parallel-projection architecture of lfg is essential to the description of a variety of otherwise recalcitrant facts about non-projecting words.