One of the sharpest changes in the evolution of Greek is the loss of the infinitive (Joseph 1978), and its subsequent replacement by na-clauses. The change is illustrated in (1) and (2):

  1. ἡ γυνὴ πάλιν φρούδη, πρὶν εἰπεῖν ἐσθλὸν ἢ κακὸν λόγον.                                (Ancient Greek)
    he: gune: palin phroude: prin eipein esthlon e: kakon logon
    the woman.NOM again gone before say.PFV.INF good or bad word.ACC
    “The woman left, before saying either a good or a bad word.” (Sophocles, Antigone, 1245)
  2. Ι jineka efije prin na pi ute kalo ute kako loγo.                                                   (Modern Greek)
    the woman.NOM left.3SG before PRT.SUBJ say.PFV.3SG neither good nor bad word.ACC
    “The woman left before saying either a good or a bad word.”

Infinitival complements were gradually replaced by hina-clauses which later became na-clauses. Infinitival loss has its origins in Hellenistic Greek (New Testament Greek, in particular), as the competing structures in (3) show:

  1. a. οὐ θέλω δὲ ὑμᾶς ἀγνοεῖν ἀδελφοί, ὅτι πολλάκις προεθέμην ἐλθεῖν
        ou thelo: de huma:s agnoein adelfoi, hoti pollakis                                    (Hellenistic Greek)
        not want.1SG but you be.ignorant.IMPF.INF brothers.VOC that often
        proetheme:n elthein
        planned.1SG come.PFV.INF
       “But I don’t want you to be unaware, brothers, that many times I planned to come.”
        (Rom. 1:13)
    b. καὶ οὐκ ἤθελεν ἵνα τις γνῷ
        kai ouk e:thelen hina tis gno:i
        and not wanted.3SG PRT anyone know.PFV.SUBJ.3SG
       “And he didn’t want anyone to know.”
       (Mk. 9:30 apud Beck 2011: 3)

Against this background of the almost total eclipse of the infinitive from the Greek language, consider infinitival retention in Romeyka (4) and the similarity to (1):

  1. Prin pisini fain, prin spudžisini so mandrin tši pao.                                                (Romeyka)
    before make.INF food before clean.INF at.the barn not go.1SG
    “Before I cook and before I’ve cleaned the barn, I am not going.”

Interestingly, Pontic Greek today (5) does not allow for an infinitive and, therefore, aligns with Modern Greek (2):

  1. prin na mairevo so mandrin ki pao.                                                                       (Pontic Greek)
    before PRT.SUBJ cook.1SG to.the barn not go.1SG
    “Before I cook I am not going to the barn.”

Although infinitives survive into Medieval Greek, infinitive in before-clauses are only found as learned borrowings and are register-specific:

  1. καὶ πρὶν ἐλθεῖν τὸν στρατηγὸν οὐδὲ εἷς ὑπελείφθη.                                      (Medieval Greek)
    ke prin elθin ton stratiγon uðe is ipelifθi
    and before come.PFV.INF the general.ACC not one was-left
    “And before the general came, no one was left.”
    Digenes (Grottaferata, IV 646)

However, although in continuous use since Hellenistic times, the Romeyka infinitive has undergone two significant changes:

  1. the syntactic distribution of the infinitive as a complement in Romeyka shows restriction to the most monoclausal domain, namely as a complement to nonveridical verbs, the prototypical licensing context for the infinitive. This is also typical of the infinitive’s distribution in Medieval Greek.
  2. The infinitive was reanalysed as a negative polarity item; that is, it came to operate under a rather constrained use, which appears to be tied to the degrees to which a proposition assumes, or rather does not assume, its own truth value. This is a development unique to Romeyka.

References in which this material appears:

Sitaridou, I. (2014). ‘Modality, antiveridicality, and complementation: The Romeyka infinitive as a negative polarity item’. Lingua 148. pp. 118-146.
Sitaridou, I. (2014). ‘The Romeyka Infinitive: Continuity, Contact and Change in the Hellenic varieties of Pontus’. Diachronica 31.1. pp. 23-73.