SpecCP

SpecCP is the specifier position of the complementizer phrase (CP) in syntactic theory. In many frameworks, CP forms the left periphery of a clause, with C as its head and SpecCP occupying the highest projection in that domain. The SpecCP position is a landing site for elements that interact with the clause’s discourse structure or its information structure, and its occupancy can reflect different grammatical phenomena across languages.

The most widely discussed function of SpecCP is in wh-questions. In languages that use A'-movement, a wh-phrase originates in a lower position and moves to SpecCP to satisfy interrogative or relativized features. For example, in English questions a wh-word often appears in SpecCP, as in What did you eat? The movement to SpecCP is typically analyzed as a way to check features associated with the C head and to satisfy the requirements of the left periphery.

SpecCP is not limited to wh-words. In languages with flexible word order or rich information structure, topics or focus fronting can also occupy SpecCP. Some theories distinguish separate left-peripheral positions, such as Spec-TopP or Spec-FocP, but many analyses treat SpecCP as a general landing site for operators, topics, or focus elements that interact with the clause as a whole.

Cross-linguistic variation is common. Some languages require or allow different elements to occupy SpecCP, and some approaches propose alternative configurations (e.g., in-situ analyses or multiple specifiers) depending on the theoretical framework and the particular language data.