This paper investigates the historical trajectory of the complement clause initiated by the conjunction se (if/whether) in Portuguese. In Portuguese and in other Romance languages this conjunction introduces conditional adverbial clauses as well. Based on records made by philologists and latinists, it is demonstrated that the similarity between these two clause types is the result of a grammaticalization process where the conditional clause passed from the adverbial function to a complement function in Latin, due to the extinction of the interrogative particles that were replaced by the Latin conditional conjunction si. On exerting a complement function, the adverbial clause initiated by se undergoes a grammaticalization process that integrates it into the main clause as a complement construction (HOPPER & TRAUGOTT, 1993; LEHMANN, 1988). However, the grammaticalization process of the Portuguese se-adverbial clause differs from the one which is predicted to occur with a complement clause introduced by que (that). Such a difference is primarily due to the hypothetical meaning that se-complement clauses carry on from its Latin historical source. Finally, it is demonstrated that the grammaticalization of clausal complement introduced by se in Portuguese is not attested diachronically, from Archaic to Contemporary Portuguese, because this grammaticalization process has been attested to occur in more remote time, particularly in 14th century texts.
Linguistic change; Diachronic syntax; Grammaticalization; Complement clause
