Two Economy Principles for Merge and Grammaticalization - with Special Reference to the Categorial Changes of Like

The purpose of this study is to show that the two syntactic principles of Merge suggested in van Gelderen (2006) named Head Preference Principle and Late Merge Principle can be employed for the explanation of the categorial changes of the word like. The diachronic research on the data from the OED and recent studies verifies the grammaticalization of the word like as a verb, and/or an adjective, an adverb, and a complementizer, especially and/or as a discourse marker. Although the distribution of the categories is overlapped, the evolution of each category implies the cyclic change of the word from head to adjunct; verb as VP-head, conjunct as CP-head and DM as SentP-head.