What is the ability to effectively communicate is important in most careers except?

It is not clear what you are trying to ask. I suggest you read novels. Lots of novels. Any novels. Take acting lessons and concentrate on vocal skills: drama or story telling.

Story tellers:
www.youtube.com/results?search_query=aaron+wilburn (Wow. Just wow.)
www.youtube.com/results?search_query=utah+phillips (Raunchy, but well told.)
www.youtube.com/results?search_query=jerry+clower (Jerry doesn't tell stories, he whoops them.)