Well, I don't think he(?) intended to promote intelligent design, but if that is his purpose, more power to him.
I'm not sure where you get that but the inadvertent modification of language by a being that has intelligence does not make the evolution of language the result of intelligent design. Design indicates an intent, something that for the most part does not occur in language change. In fact language changes more or less at random as pronunciation and primary meaning drifts from one generation to another and words from other languages are co-opted.
Claiming intelligent design for any and all connections between humans and a process, no matter how tenuous the link to 'intelligence' or 'design', broadens the definition of 'intelligent design' to a point where it becomes meaningless.
If I take a page of letter size paper and fold it into a paper airplane that paper airplane can properly be called intelligently designed. If I take that same paper and crumple it into a shapeless mess, the shapeless mess is not intelligently designed even though I have some modicum of intelligence. Please do not point out that the paper is 'designed', the origin of the paper is a separate issue, we are concerned with the result of my actions, not a paper mill's.