I find the stroke anecdote fairly unconvincing. The man clearly still had the capacity for language - he was miming the action of a tennis racquet. Sign language is still language. Just because something went haywire between his brain and his mouth doesn't mean he lacked language.
I also don't think you can easily dismiss the conscious of animals by saying they lack language. Most animals (dogs, whales, birds, etc) seem to engage in limited communication via audible signals.
As with most philosophical questions, though, it all hangs on the definition of "consciousness". It may not even be a concept worth defining.
It is certainly communication, but I think there's a difference between communication and language. The latter requires more structure: perhaps grammar, a finite fixed set of predetermined words, etc.
You don't really need consciousness to communicate, since it's just transfer of information between different entities - for example, an organism could secrete chemicals that are detected by neighboring members of the species, as I think it's the case for some plants.
Structured communication might be different, as I think there has to be a something that composes the particular "phrase".
What I understood from reading Noam Chomsky is that language was reduced to being able to speak (collectively, not in a human by human case). That in this, we were a unique species.
Your second point is what came to mind when I read it, and found it rare that no one has pointed that out: dogs and cats can definitely express themselves to some degree of complexity, and we can say that they have language.
I mean, at 6 am, when my dog starts barking, he definitely means he's hungry, and we both know that: knowledge has been conveyed, and thus, it's a form of language.
Has anyone any insight on this? Have I misunderstood Chomsky?
See my other reply in this post why I thing he is wrong about universal grammer. I don't have any problem conceiting that humans are the only species with advanced language skills ;)
Fwiw, it appears you're saying "[human] sign language is complex; simple use of physical signalling is not language". But, your statement could be read as disparaging sign language as "not language", something I'd strongly refute.
I said that sign language has linguistic structure so it's language.
Proper language requires this structure, just making sings is not automatically language. Just the ability to signal using single atomic words, in some medium (signs, verbal, written, machine) is not a language.
The whole piece is fluff. It focuses on one or two minor, anecdotal observations regarding aspects of ideas about consciousness. The fact alone that in split-brain patients consciousness is often not preserved in the left hemisphere undermines all speculation involving cytological similarities between species.
I feel like this is a good place to recommend the Radiolab episode Words [1], though it's not so much about consciousness as about language, the development of language, and communication without a shared language. I found it a very intriguing listening experience, hope others will enjoy it as well. Part is about the man without words mentioned elsewhere in the comments as well (a person who learned language as an adult).
I also don't think you can easily dismiss the conscious of animals by saying they lack language. Most animals (dogs, whales, birds, etc) seem to engage in limited communication via audible signals.
As with most philosophical questions, though, it all hangs on the definition of "consciousness". It may not even be a concept worth defining.