A non-finite period in early Cypriot Greek?

In the literature on the acquisition of the morphosyntax of Standard Greek at the early stages (SG), it is noted that children overuse a verb form that employs the suffix - i , often referred to as 3 rd person singular (3SG) (Katis 1984; Stephany 1981, 1997; Tsimpli 1992/1996). Varlokosta et al. (1996, 1998) claim that this form, which appears with perfective aspect, is not the 3SG, but a non-finite form of the verb, comparable to the (non-finite) Root Infinitives (RI) cross-linguistically. It is the same non-finite form encountered in periphrastic Tenses, e.g. exo/ixa peksi . Cypriot Greek (CG) lacks Present Perfect A, and other periphrastic tenses are used minimally, mostly when interacting with SG speakers (Melissaropoulou et al. 2013). One would think, therefore, that CG-speaking children receive less input of these non-finite forms, and wonders what the early non-finite verb form of CG is. We collected spontaneous speech from three CG-speaking children, aged 1;07 to 2;03. Two of them were followed for a short period of time (at 1;07, 1;08 and 2;00, 2;02) and one over a period of seven months, (1;07 to 2;02), once per month. We found that the non-finite form of early CG, in terms of a non-agreeing form of the verb, is the 3SG form. However, it does not appear exclusively with perfective aspect; instead, perfective and imperfective aspect morpheme are split in half. Given that CG has no infinitives, we conclude that this is the only form of the verb able to fulfil the needs of early language, since 3SG has been argued to be the least specified form in Greek and cross-linguistically (Tsimpli, 1992/1996; Varlokosta et al. 1996, 1998; Harley and Ritter, 2002; Ferdinand, 1994; Grinstead, 2000). Of particular interest is that only 3SG forms with perfective aspect demonstrate all the properties associated with RIs in the literature (Hyams, 2002 a.o.), posing the question of how come it is possible for a form to be non-finite, yet, not have RI properties.