Bear in mind that taking twenty is effectively useless with this skill. You can read at four minutes per page and take ten to get the same effect. That may have been intentional, but it merits pointing out.
Also note that, if somebody uses a complex cypher, anyone who speaks the encoder's language can decode the entire page in four minutes untrained using the above trick. The same thing applies to distantly related languages and coded messages--If I read it right, if somebody writes "I think Mister Abernathy is cute. I'd so like to go out with him. We could, like, buy ponies and drink champagne and I bet he'd get me that CUTE sweater I was talking about!", which is code for "set the bomb in apartment 115 and rig it to blow at 1400 hours," anyone who speaks English will understand this if they only spend four minutes looking over it!