“But his mother said.
He is to be
καὶ ἀποκριθεῖσα ἡ μήτηρ αὐτοῦ εἶπεν Οὐχί, ἀλλὰ κληθήσεται Ἰωάνης.
Luke said that Elizabeth, the mother of the child, intervened (καὶ ἀποκριθεῖσα ἡ μήτηρ αὐτοῦ). She said no (εἶπεν Οὐχί), that his name was not going to be Zechariah, but he would be called John (ἀλλὰ κληθήσεται Ἰωάνης). I guess that during the 9 months of pregnancy, the 2 parents had agreed on what Zechariah had been asked to do.