That journeyed with him (hoi sunodeuontes autōi). Not in the older Greek, but in the Koiné, with the associative instrumental.
Speechless (eneoi). Mute. Only here in N.T., though old word.
Hearing the voice, but beholding no man (akouontes men tēs phōnēs, mēdena de theōrountes). Two present active participles in contrast (men, de). In Act 22:9 Paul says that the men “beheld the light” (to men phōs etheasanto), but evidently did not discern the person. Paul also says there, “but they heard not the voice of him that spake to me” (tēn de phōnēn ouk ēkousan tou lalountos moi). Instead of this being a flat contradiction of what Luke says in Act 9:7 it is natural to take it as being likewise (as with the “light” and “no one”) a distinction between the “sound” (original sense of phōnē as in Joh 3:8) and the separate words spoken. It so happens that akouō is used either with the accusative (the extent of the hearing) or the genitive (the specifying). It is possible that such a distinction here coincides with the two senses of phōnē. They heard the sound (Act 9:7), but did not understand the words (Act 22:9). However, this distinction in case with akouō, though possible and even probable here, is by no means a necessary one for in Joh 3:8 where phōnēn undoubtedly means “sound” the accusative occurs as Luke uses ēkousen phōnēn about Saul in Act 9:4. Besides in Act 22:7 Paul uses ēkousa phōnēs about himself, but ēkousa phōnēn about himself in Act 26:14, interchangeably.