speechless
From LSJ
πάντα χωρεῖ καὶ οὐδὲν μένει καὶ δὶς ἐς τὸν αὐτὸν ποταμὸν οὐκ ἂν ἐμβαίης → all things move and nothing remains still, and you cannot step twice into the same stream
P. and V. ἄφωνος, V. ἄφθογγος, ἀπόφθεγκτος, ἄφθεγκτος, ἀφώνητος, ἄλαλος, ἀνεπής, ἄναυδος.