What orders the Romance clitic strings? Against precompiled hierachies

Our main goal is to argue that clitics can be sequenced without resort to stipulated hierarchies – adopting the view that linear order of terminals belongs not to the core computational component (Kayne 1994, 2010) but to the externalization procedure for syntax (Chomsky 2001, 2005, 2013). Thus we impute the order of non-clitic constituents to the combination of two factors. In core syntax, the verb Merges first with the internal argument, and then with the oblique argument, yielding {{V, DP}, to DP}, where the set notation corresponds to the presence of simple sisterhood relations (Chomsky 1995). An externalization parameter chooses the head-initial order, whereby the head (i.e. the labelling item) and the constituents including the head are ordered before complements.