ὑπότραυλος
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
English (LSJ)
ὑπότραυλον, lisping a little, Hp.Epid. 7.3.
German (Pape)
[Seite 1236] ein wenig stammelnd, stotternd, Hippocr.
Greek (Liddell-Scott)
ὑπότραυλος: -ον, ὁ τραυλίζων ὀλίγον, γλῶσσα ὑπότραυλος ὑπὸ ξηρότητος Ἱππ. 1207Ε.