Most Helpful Guy
As a radio broadcasting student I can tell you that they are usually not scripted but the talent are given a run down sheet which tells them loosely what to talk about and when and then they provide their own commentary on the topic.
Fun fact: most of what you hear on the radio isn't live to air, meaning it isn't being said at that very moment. About 70% of a 3 hour radio show is pre recorded, segments like phone calls are edited heavily to remove any silences or pauses and segments with celebrity's ain't done live either.
- 2 years studying a bachelor of Commercial Radio Broadcasting.1