From dialegomai; a (mode of) discourse, i.e. "dialect" -- language, tongue.
see GREEK dialegomai
1. "conversation, speech, discourse, language (Plato, Demosthenes, others).
2. from Polybius (cf. Aristotle, probl. 10, 38 τοῦ ἀνθρώπου μία φωνή, ἀλλά διαλεκτοι πολλαί) down, the tongue or language peculiar to any people: Acts 1:19; Acts 2:6, 8; Acts 21:40; Acts 22:2; Acts 26:14. (Polybius 1, 80, 6; 3, 22, 3; 40, 6, 3f; μεθερμηνεύειν εἰς τήν Ἑλλήνων διάλεκτον, Diodorus 1, 37; πᾶσα μέν διάλεκτος, ἡ δ' Ἑλληνικῇ διαφερόντως ὀνομαατων πλουτει, Philo, vit. Moys. ii. § 7; (cf. Muller on Josephus, contra Apion 1, 22, 4 at the end).) STRONGS NT 1258a: διαλιμπάνω [διαλιμπάνω (or διαλυμπάνω): imperfect διελιμπανον; to intermit, cease: κλαίων οὐ διελίμπανεν, Acts 8:24 WH (rejected) marginal reading; cf. Winers Grammar, 345f (323f); Buttmann, 300 (257). (Tobit 10:7; Galen in Hipp. Epid. 1, 3; cf. Bornem. on Acts, the passage cited; Veitch, under the word λιμπάνω.)