Come back when you've hooked up NASA's subvocalization detector to a Chinese man and seen it register nothing while s/he reads.
In fact, many of the "hints" in the written symbols are based on words that sound similar to other words when pronounced (their actual meaning being unrelated), which is fully lost if you cut out the vocalization. As another point, most words are written with multiple symbols, and the meaning of the overall word may be rather different than the words you would get if you read the symbols individually. At that point, I don't see any difference from a word written with an alphabet like English.
I posit that if you were a native Chinese speaker, you could skim (or speed read as claimed in the article) without any subvocalization and still understand the given passage.
1: http://en.wikipedia.org/wiki/Talk:Subvocalization#Subvocaliz...