Is learning the English Opening helpful for learning the Sicilian Defence? How about vice versa? Is learning the opening 1. c4 e5 as white helpful in learning the opening 1. e4 c5? How about vice versa?

Are the ideas behind the Sicilian Defence as black very similar to the ideas behind the English Opening as white?
I'd say learning the Sicilian is great for playing the English. Ideas from the Closed Sicilian, King's Indian attack and many others appear all the time in the English with reversed colors.

However, I don't think it works the other way around, as the main lines in the Sicilian come form the opened variation, where the extra tempo is often critical and therefore the ideas played change way too much.