Variation in the pronunciation/silence of the prepositions in locative determiners

We argue that the micro-variation observed in the pronunciation/silence of the prepositional head of locative determiners in Fallese, a dialect spoken in Abruzzi, follows from the option of valuing features by either External Merge or by Internal Merge, given Spell-Out conditions, whereas this option is not available in English and Italian. It follows that the prepositional head is silent in Italian and English, whereas it can be pronounced in Fallese when the Specifier of the locative determiner is not filled. We show that this feature-based approach to micro-variation, in conjunction with principles of efficient computation, makes correct predictions for the pronunciation of the prepositional head in other functional categories, as well as it makes predictions on the diachronic development of locative determiners Latin to Fallese and from Latin to Italian, otherwise it looks like Fallese is an old stage of Italian.