commentator:
(also ‘commenter‘; ‘c’ in this word is pronounced with a ‘k’ sound as in “king” — for the right pronunciation of this word,
please click here)

a radio sports commentator
a person, with a clear voice and good language, who narrates (or tells about) an event, especially when the event is going on, such as a football match, a boxing match, a show, a news item, weather on radio or TV, etc., usually as an occupation/job;
a person, an expert, who observes or examines some issue or someone and says something (comments) in a clear way, often adding their own opinion, about those events to make the general public aware of the issue or person;
a writer who reports on an event(s),

a female political commentator
Andrew wants to be a political commentator, and he’s taking lessons on how to become a good commentator.
There are different types of commentators: sports commentators, political commentators, radio commentators, blog commentators, etc.
Commentators must have a thorough knowledge in the subject they are commenting on, for instance, a football commentator should know the rules and regulations of the football game and also about the previous victories and defeats of most of the top teams and players.
