Loquacity is the quality or state of being very talkative
. . . and one thing for the future bear in mind, that thou curb and restrain thy loquacity in my company; for in all the books of chivalry that I have read, and they are innumerable, I never met with a squire who talked so much to his lord as thou dost to thine; and in fact I feel it to be a great fault of thine and of mine: of thine, that thou hast so little respect for me; of mine, that I do not make myself more respected.
From Cervantes's Don Quixote.