babilado

Babilado is a genuine build, and one of the tidiest in the language: babili, to chat, plus -ad-, the suffix for the action considered as something ongoing. Babili is what you do; babilado is the chatting, the activity as a thing with duration.

That is the whole job of -ad- and it is worth getting straight, because the noun ending -o alone does not do it. Babilo would be a single chat, one instance; babilado is chatting as an ongoing business, the sound of a room. Compare paroli -> parolado (a speech, or talking as an activity), kanti -> kantado (singing), labori -> laborado (toil, work going on and on). The aspect affixes article sets -ad- beside ek- (the sudden start) and -iĝ- (the change of state), which is the right company for it: they are all about the shape of an action in time rather than its content.

Register: babilado is warm but faintly dismissive, the way "chatter" is in English. A conference has prelegoj in the hall and babilado in the corridor, and everyone knows which one they came for.