You opened a can of worms for me. As a non-native (but very comfortable) English speaker I wasn't quite sure about the pronunciation of "eschew" because I can't remember to have ever used it, or when I last heard it.
Native English speakers are in the same boat a lot of the time. My reading vocabulary is a strict superset of the words I know how to pronounce, and I suspect the same is true for everyone who speaks a language with a non-regular writing system.