This paper is aimed to investigate the structure of Korean pseudo-cleft constructions with the bound noun kes in subject position, by examining the asymmetry between two kess in the subject position of pseudo-clefts and in the pre-copula position. The paper argues that the former can represent a human entity as well as non-human elements because it is universal. It denotes a set of presuppositionality, and thus, it has to raise to SpecTopicP through the predicational inversion. As a result, it precedes the foci in specificational constructions. The other is specific, denoting only a non-human material thing. Thus they don’t appear in specificational reading but in predicational, which requires agreement between the subject and the complement. Conclusively, Korean has two different types of kes in pseudo-cleft constructions.

This article deals with the diachronic change of pseudo-clefts in which the clefted constituent, i.e. focused part, is realized as a verb, i.e. to-infinitive, bare-infinitive, -ing. (e.g. What/All he did was help/to help her. What/All he was doing was helping her.) The analysis of the Corpus of Historical American English (COHA, 1820-2009) shows that to-infinitive is the oldest construction but was not frequently used until the early 1800s from which its use rapidly increased until the early 1900s. It was then overtaken by its competitor, the bare-infinitive, in the 1950s-1970s and fell into decline. The bare-infinitive is the early 20th century innovation rarely used before then and shows a rapid rise throughout the 1900s. The occurrence of -ing is found from the early 1900s and gradually increases until now. The replacement of to-infinitive by bare-infinitive was lead by all-clefts rather than what-clefts: All-clefts are not only higher in the overall frequency but earlier in the innovative use of bare-infinitive.