"Urban Dictionary", an otherwise useful resource, has no definition for "dudespeak." There is this, but frankly it's not that helpful.
In fact, I have not found any good entries anywhere on definitions.
This one cartoon is quite useful, but it is simply an introduction. (on the other hand, it does contain the second law of thermodudenamics, so it is a delight: "In all isolated cultural exchanges, irony increases.")
It appears to have a specific meaning. World of Warcraft, for example, specifically bars character or pet names that contain "Leet" or "Dudespeak." (No, don't ask how I know that.) Now, leet is well defined. And Wikipedia has this on "dude". But...not good. And, there is this, too. And this meditation on dudity, from an outside perspective.
Clearly, the language is important. There is already a "Dude to English" lexicon.
What is "dudespeak", and how would one know if a sentence or expression were an example?