Acquainted and friendly; in a state where salutations and general remarks can be comfortably exchanged.
2017 August 22, Hillary Richard, “The Wonder Women of Botswana Safari”, in New York Times[1], archived from the original on 2017-08-22:
Ms. [Gomotsang] Modibu considers herself to be on speaking terms with the animals she sees every day. She sees them as her colleagues.
2018, Christopher Markus, Stephen McFeely, directed by Anthony Russo and Joe Russo, Avengers: Infinity War (motion picture), spoken by Tony Stark/Iron Man (Robert Downey Jr.):
Cap [Captain America] and I fell out hard. We're not on speaking terms.
