Verbal and nominal plurals and the syntaxmorphology interface

One of the assumptions of the Minimalist Program (Chomsky, 1995, and subsequent work within the program) is the idea that (narrow) syntactic derivations are driven by the interaction between formal features. However, one key aspect of formal features that drives their syntactic activity is the lack of interpretability. Thus, non-interpretable agreement features on temporal and verbal heads must be paired with interpretable matching features on nominal elements such as subjects and objects. There is compelling morpho-phonological evidence from Arabic that this dichotomy is plausible and has far reaching consequences for the syntax-morphology interface. The critical argument comes from cases of nominal and verbal plurals where the plural feature is spelled-out differently depending on whether it is interpretable or non-interpretable on its immediate host.