Well, I'm not sure cognition entirely without language is even possible for non larval humans. Language is a natural tendency and it arises regardless of documentation, scribblings or utterings. It exists whether audible or not. Language itself is manifestation of the thinking process that permits it.
And I'll hold to the notion that the complete absence of language (and its underlying structure) would resemble death if death can be resembled. Perhaps death is only the excoriation of thought, cognition and language, with something more fundamental persisting.