Oral

Of words that are enunciated. Spoken. Uttered. Vocalised. Phonated. Rendered through the vibration of twin infoldings of membrane stretched horizontally across the larynx, thus modulating the flow of air being expelled from the lungs.

A lesser adverb than verbal, and all the less useful for it. When your circumstances seem to call for the flannel-cut expression orally or in writing, consider verbal instead.