The voice coach
On a plain run, such as an easy run, a long run or a recovery run, the coach says Run start and the run's distance as you start, and Workout complete when you reach it. On a session with steps, such as tempo, intervals or hills, it says each step as it starts, with its distance or time and its pace, says when each step is complete, and Workout complete at the end. A free run says Run start and nothing more.
Pace alerts come only on a session's work steps, when you drift off the target pace. On an Apple Watch, Mile callouts also say each mile and its pace, on any run; they have their own switch in the watch's settings.
Turn the coach's cues on or off in Settings, Voice cues. Pace alerts has three choices: Voice and buzz, Buzz only (Apple Watch) or Off. On the phone, the speaker button on the run screen mutes the coach for that run. The watch's own settings hold Haptics and Mile callouts.
Profile, the gear, Settings, Voice cues or Pace alerts.