"Speaking and writing are termed productive because these skills require active participation on the part of the student such as writing a paragraph or answering a question."
My original inference was that reading was passive. Here's their attempt to clean this up:
So, they've cleaned it up...or have they? In fact, what they've said is that the brain, on a physiological level, and a cognitive level, is active. That is to say that human beings, especially those dealing with a foreign language, have to use their brains to understand the text they're reading or the language they're listening to. However, what they in no way mention is the act of meaning creation as an activity in which the student is involved. They make no mention of hte flitering that the message contained within the text undergoes in its spacially short journey from the page in a book to the brain a mere two feet away.