Does your brain make a distinction between vocal and non-vocal language?

Question

Language noob here. Just curious; does are body, while learning a language, make a distinction between spoken language and sign language? Or are they all just inputs and outputs to your brain? Each just as able to be incorporated in the language production/comprehension process?

Basically, from a language development standpoint, are our vocal-cords, tongue, glottis, etc. special? Or are they all just muscles; with your hands, feet, neck, etc. being just as valid to your brain?

Sorry if my question's sloppy. Still new to this part of SE. But you know, are our speech producing muscles inherently special, or just most commonly used in the language development process?

Answer 1

Spoken and signed languages are distinguished in the brain in different ways. From the perspective of perception, spoken language is processed in the cochlear nucleus of the brainstem and then the primary auditory cortex, whereas signed language is processed by the lateral geniculate nucleus in the thalamus and then the visual cortex. As for production, different areas of the brain control muscular movements for speech apparatus versus hand, arm and facial movements in signed language.

The glottis actually is not a muscle, it is a hole, defined by the vocal folds, which are also not muscles, they are mucous membranes. The speech organs of humans are special from the perspective of comparative mammalian anatomy, since we have greater volitional control over these organs; of course it would be comparing apples to oranges to compare control over the tongue versus the hands.

Brains don't treat any body parts as being invalid.

Some people think that there is no difference between brain processing of language and brain processing of any other stimuli, but I think the evidence does support the view that language is special.

Answer 2

There really isn't just one high-level, abstract, "language production/comprehension process". That view would be much Chomskian and is now generally derided. Language production/comprehension is the result of cooperation between several cognitive capabilities. There are definitely overlaps for spoken and sign languages, especially in meaning comprehension and production (not in the sense of the final muscle movement, which is different of course). There would also be differences, in terms of concrete perception mechanisms.

Language acquisition researchers also looked into the acquisition of sign languages (e.g. for children that are born deaf). Those who had normal parents showed demonstrably worse results than those with also sign-language using parents, presumably because the normal parents can't provide an immersion environment. This is the same as what happens in the acquisition of spoken languages.