[greymule]

I guess you could consider verbal to be a subset of oral in the way you described. The mouth has many uses, one of them to utter words (and I've never heard of verbal sex). But it's more often the other way around. Verbal, in the sense of "by means of words," is usually thought of as including oral communication. So when we instruct someone, "Be sure to communicate this verbally to Frank when you see him," the person we're talking to might think that a written document would be OK, when spoken words were what we had in mind.

Someone might argue that all oral communication might fall under the umbrella of verbal communication, but I guess that a scream or a grunt, which is certainly oral, would not technically qualify as verbal.

(In the work I do, this distinction actually matters.)

Incidentally, biting would be interference, but I've never seen it in baseball or softball. I did see it once in basketball, though. The ref called a foul and ejected the player. There is a well-known case in boxing, too.

See usage note from American Heritage Dictionary:

"Verbal has been used since the 16th century to refer to spoken, as opposed to written, communication, and the usage cannot be considered incorrect. But because verbal may also mean “by linguistic means,” it may be ambiguous in some contexts. Thus the phrase modern technologies for verbal communication may refer only to devices such as radio, the telephone, and the loudspeaker, or it may refer to devices such as the telegraph, the teletype, and the fax machine. In such contexts it may be clearer to use the word oral to convey the narrower sense of communication by spoken means."

Since interference by written word is highly unlikely in softball, I would say that "verbal interference" is a fully acceptable term.