|Abstract:||This paper focuses on a case of prosodically-driven morpheme non-realization found in Minorcan Catalan kinship restrictive appositional phrases, in which the personal article en is realized before masculine personal names starting with a consonant, but not before masculine personal names starting with a vowel, or before feminine personal names starting in either a vowel or a consonant. From a strictly syllabic point of view, this pattern is unexpected, since a preconsonantal coda is generated in the former cases, and an onset-less syllable and a hiatus are generated in the second. Following work by Selkirk (2001), we propose that this asymmetric behavior is mainly driven by the constraint ALIGN(PWd, L; Lex), according to which the left edge of the prosodic word must be aligned with a lexical category. We show that, whereas it is possible to satisfy this constraint without challenging basic syllabification constraints (i.e. *C.V, ONSET) when the personal name starts with a consonant, this is not possible when the personal name starts with a vowel. The effects of the alignment constraint are inhibited by the need to realize phonologically the morph corresponding to a morpheme when the information it carries is not recoverable, and this explains the realization of the personal article in isolated constructions. The interaction of ALIGN(PWd, L; Lex) with standard right-alignment requirements, finally, accounts for the lack of realization of the feminine personal article before feminine personal names in these appositional phrases. The data taken into consideration and the subsequent formal analysis allow us to explore the nature and the typology of morpheme realization constraints, and to assess the theoretical consequences for the phonology-morphosyntax interface and for the architecture of grammar.