Separability of Derivational Phase Edge in a Persian Compound Verb

Compound verbs in Persian are verb constructions formed by more than one simple lexeme. For example, negah kardan (literally “watch do”) is a compound verb made of a nonverbal element negah (watch) and a light verb kard-an (to do). Syntactically, they are heads which can split during sentence derivation. The light verb kard-an, merged with a nonverbal element, comprises a compound verb and it cannot determine argument and transitivity of a verb alone. If such compound verbs are lexical words, then they should not split in the sentence structure by syntactic operations. On the other hand, if they are syntactic constructions then forming a new lexeme after syntax floats some theoretical conditions. The purpose of this paper is to describe the derivational steps of one type of compound verbs and explain how it is separable in syntax. Some of the data are selected from Sokhan Dictionary and some other (used in the sentence structure) from the online version of the Persian Linguistic Database (PLDB). The results indicated that Persian compound verbs are morphological phases the edge of which is visible and accessible to syntactic operations. First, the roots negah and kard enter merging, and after merging of a phase head involving [Tense] feature (usually, a light verb category), the root kard adjoins it to obtain the [Tense] feature. Finally, if root negah remains at the phase domain (under the phase head) it should transfer to the interface levels and become inaccessible to the moved kard at the phase edge. Therefore, negah should move to the phase edge; otherwise; kard and negah should be interpreted in two different phases and could not join to form a compound verb. That is, negah is also absorbed to Spec-phase by the [EPP] feature of the phase head. Now, both of them are regarded as a compound verb and the nonverbal element at the phase edge is accessible to the syntactic operations. Hence, it can split in syntax (for more details, see Heidarizadi, et al, 2017). Finally, following Johnson (2003) a syntactic operation called "renumeration" is introduced which targets the nonverbal element at the morphological phase edge and splits it, hence leads to its separability in syntax as the derivation proceeds.