1. (a) That's right. In everyday language (and in the criminal law) the word assault implies physical contact. But a plaintiff suing in tort for assault need only prove that the defendant has behaved in a way that made the plaintiff expect or fear imminent (immediate) physical contact, most often of a harmful nature. Assault is an instance of trespass to the person.
Although verbal threats are usually accompanied by other threatening conduct, it should be noted that making verbal threats alone might be construed as threatening conduct sufficient to inspire the necessary fear of harm.