De-phased by external pair-merge of C to T and its consequences

This paper aims at the possible application of external pair-Merge of C to T (<T, C>), based on the proposal of Epstein et al. (2016) and its consequences. Chomsky (2004) argues that internal set-Merge comes for free as well as external set-Merge, and suggests that there is an operation of pair-Merge. It also applies either externally and internally. Therefore, there are four possible sub-types of Merge operation. I argue that external pair-Merge of phase heads to non-phase heads brings about de-phasing effect (a cancellation of phases). As a consequence, we can derive ‘grammatical’ derivations for some cases of improper movement, including tough-constructions in English. Furthermore, we can get the desirable prediction for Mergeover-Move principle in terms of labelling.