First of all, I am not a linguist, but I was thinking the other night that being literate was almost the same as being bilingual.
My reasoning is that sign language is distinct from written and spoken English, and sign language is a "visual" language in the same way that written English is. Also, homonyms and homophones would be entirely analagous, if these are considered different langauges.
It seems to me that the only reason they could be considered the same language, is that they follow each other so closely. That is, there are many one-to-one literal translations between them.
This distinction is relevant in natural language processing contexts, because it would mean that "understanding" a language and "translating" between languages would be distinct problems. I believe that this could reduce the problem space substantially.
Surely, I am not the first person to think this, but as I have no formal training on the subject; I'm not sure what the real story is. So, Are written and spoken languages considered distinct? If not, why not?
Sign languages and spoken languages are both real, natural languages, learnable and normally learned automatically by children -- without any special training -- if they are used in the speech community the children grow up in.
Written languages, however, are always representations of some spoken language; one has to be specially trained in the technology of literacy.
An analogy is horses vs cars -- horses are natural, cars are technological. Horses have drawbacks and limitations compared with cars as a means of transportation, but one big advantage of horses is that they can make more horses without a factory, or even any education.
The fact that most people in a community are literate does not automatically result in the children of that community becoming literate, the way a common language generates new speakers (or signers). They have to go to school -- no school, no literacy.
But they all speak or sign, whether they're literate or not.Tweet