Where did Late Merge go? Grammaticalization as feature economy

Within early Minimalism, there are Economy Principles such as 'Last Resort', 'Least Effort', and also 'Merge as Late as Possible'. The latter principle makes it possible to explain grammaticalization, an important phenomenon in language change. The general direction of change is one where lexical items are reanalyzed as grammatical (or functional) categories, e.g. verbs as auxiliaries and prepositions as complementizers. One explanation in terms of Late Merge is that if a lexical item is not immediately relevant for theta-structure, it can wait and merge later, rather than merge early with additional movement. In later Minimalism, move is reformulated as internal merge and not considered more uneconomical than regular merge, renamed as external merge. This paper will provide ample examples of the workings of Late Merge and examine how we can capture the grammaticalization effects through an Economy Principle, Feature Economy, that is at work when children acquire a language as well as when language changes.