Mid 19th century; earliest use found in Edward Bulwer-Lytton (1803–1873), writer and politician. From over-talk.
1To win over or overcome (a person) by talking; to out-talk.
2(reflexive). To talk excessively. Also occasionally with object: to talk too much about or make too much of (a subject).
Early 17th century. From over- + talk.