Nanosyntax is a new approach to the architecture of grammar, which integrates the results of 30 years of Principle & Parameters research as well as the growing structuralisation of semantics
The essential building block of nanosyntax is the simple observation that the terminal nodes of syntactic structures have become very small as syntactic trees grew, and at some point they crossed the line to become smaller than a morpheme -- terminals have become "submorphemic". This simple fact, noted many times, leads to profound and wide-ranging consequences once it is taken seriously.
One immediate consequence is that morphemes and words can no longer be the spellout of a single terminal. Rather, a single morpheme must "span" several syntactic terminals, and therefore corresponds to an entire syntactic phrase. This in turn means that entire syntactic phrases are stored in the lexicon (not just terminals) and it also means that there cannot be any lexicon before the syntax - i.e. syntax does not "project from the lexicon".
This apparently innocuous technical change has wide-ranging consequences, both technical and architectural (e.g. there cannot be a lexicon before syntax and hence syntax does not "project from the lexicon", syntax rather "creates" lexical items by assembling the trees which will constitute lexical items). We are very excited to be exploring this new world and making better sense of the empirical results of current syntactic research.