To communicate with (someone) by means of a signal.
To furnish (a traffic intersection) with a traffic signal.
To indicate; to be a sign of.
To communicate (some fact or feeling); to bespeak, to indicate.
To communicate with one's voice, to say words out loud.
To understand (as though it were a language).
To have a conversation.
To utter.
To produce a sound; to sound.
To be able to communicate in a language.
Of a bird, to be able to vocally reproduce words or phrases from a human language.
To deliver a message to a group; to deliver a speech.
To be able to communicate in the manner of specialists in a field.
To communicate or converse by some means other than orally, such as writing or facial expressions.
Speech, conversation.
language, jargon, or terminology used uniquely in a particular environment or group.