In this dissertation, I investigate Tagalog second position clitics in a new empirical depth concluding that these elements are best treated as "non-syntactic" adjuncts to phrase structure. This approach is thus most similar to Anderson's (1992 et seq) "phrasal affix" analysis of clitics but differs in several important respects. Second position clitics are understood here as the spell out of feature bundles which are adjoined to phrase structure in the syntax via an operation Merge (Feature). Unlike bona-fide syntactic heads which are introduced via Merge (Terminal), these feature bundles are not housed under a terminal node within the phrase structure. Nonetheless, limited interactions with syntactic structure are possible. For instance, second position clitics are conjoinable in Tagalog under special conditions and must comply to a locality restriction with the predicate phrase from which they receive their theta-role, two interactions which are highly unexpected on a purely morphological understanding of these elements. I also review Klavans' (1980 et seq) clitic typology paying special attention to clitic type. I conclude that, once unambiguous morphosyntactic sister clitics (typically syntactic heads) are separated out, two new generalizations emerge: (i) sister clitics can only be manipulated by bona-fide syntactic movement whereas non-sister clitics can be displaced due to phonological factors, (ii) sister clitics can attach phonologically to or away from their complements whereas non-sister clitics cannot attach phonologically to an element outside their syntactic domain. These findings revise our understanding of the repertoire of available clitic positions and attachments, leading to a welcome simplification. Syntax and phonology are thus not seen to be independent with regard to clitics, as previously claimed (Klavans 1980 et seq). A wide range of syntactic facts concerning Tagalog clitics are also covered here for the first time leading to a new characterization of clitic impenetrable constituents. Impenetrability is shown to be a property of pronominal argument clitics rather than adverbial clitics and requires a locality relation between pronominal arguments and the predicates with which they are associated. This locality condition accounts for the full range of data in a way that cannot be done by previous approaches.