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
Celt, Kelt = Κέλτης
Celts, Kelts = Κελτοί, οἱ, Κελταί, οἱ.
Celtic, Keltic, adj.: Κελτικός.
