Verbiage or talking too much is a common mistake in improvisational theatre. Talkativeness means that more is spoken than does good to the particular scene or the present performance, from which the best possible is not produced. Verbosity does not mean the scene or situation is failing. Too many speeches lead to the risk of a boring, static, non-animated scene. Monologues, instead of enlivening, impede or hamper the actor's emotions and vivid, more intense and immediate "perceptions" and experiences, or they frustrate changes of situation on the stage.
Talkativeness can show up in several situations.
It is play-by-play saying or announcing what one also does or will do. Example: "I am now screwing in the light bulb" and that's precisely what is done while saying it, or immediately before of after saying it (rule of thumb: "don't talk about it - just do it").
Just talking about a situation, instead acting it out/showing it. For example, someone says, "I'm hungry" and moans and complains about it. Better: he looks in vain and extensively for food in the cupboard, the refrigerator, etc.
Events are spoken of (at length) which are not present: "Helga had fought with me yesterday. She wanted me to empty the trash. But I had started to do somethin' else. Then the telephone rang, too." etc. Better: proceed in acting out a flashback.
Even though the current scene is dramaturgically "exhausted" or "sucked dry" (see also Beat), it isn't ended or interrupted but instead talked about (further). That means that there will be no new momentum from a leap in time for instance, or by a player coming into the scene.
It quashes an existing or arising feeling. That is, a silence of several seconds would be more intense and would strengthen the feeling. Example: two old friends meet one another again after many years. Here, a silent, warm embrace is much more moving than many words.
Chattiness is frequently the expression of lack of knowledge, confidence and experience. One thinks that the audience can't stand silence, or it's boring for them. That can also be the expression of the player not yet having learned to work in physicality, in movement, in pantomime. Finally, verbosity can indicate non-awareness of the beat: the well-timed cut-off was missed.
If it is stylistically well refined, however, chatter can also be used well.
In Shakespearean plays, what one intends to do soon is always announced, and then also explained during the act itself.
In Chekhov's plays, there is constant whining without anyone actually doing something to solve the problem.
Indeed a verbose character has comic potential.
It is crucial that the verbosity is viewed positively in terms of the performance, and the actor is clear that the scene is not necessarily moving forward, now.