week17-Why do humans choose to speak rather than sign language?

"It is no accident that human language uses sound as a means instead of gestures or pictures. Human vision is the most developed, but language appeals to hearing. This is because all means that rely on vision cannot function without light , It won’t work at night, and it won’t work in dark places or places with obstacles. Sound can play a role day and night, and it’s not easy to be hindered. Gestures and the like can’t be seen clearly at a large distance, and the effective distance of sound is much greater. When gesturing or drawing, you need to use your hands, and your hands can’t do other things at the same time. You can speak with your mouth, and you can work while talking. In terms of speed, gesturing can’t keep up with talking, and drawing can’t keep up. The only thing is that the voice is not as good as the image However, in the actual situation of primitive society, this requirement is secondary and can be supplemented by graphics. In short, it is precisely because the voice of the mouth is used as a means, It is only then that human language has been developed with great promise.” ——"Human Language" by Mr. Lu Shuxiang

1. What human beings evolved must be body language, not speech system. The emergence of speech must follow the evolution of human tongue, mouth, sound recognition system, speech control ability, brain structure and mechanism to a certain stage. , which must be later than body language. There is no definitive conclusion as to when the specific speech was produced. There is a hypothesis that speech appeared after the appearance of Homo sapiens. According to this theory, it is believed that speech cannot be produced before the throat descends to the front of the laryngeal cavity. Therefore, Neanderthal There are opposing theories about the impossibility of man speaking the language of modern man.

2. It is said that sign language is not as good as speech (in fact, sign language is scientifically divided into speech, which belongs to language), which is also somewhat arbitrary. Human beings produce speech to communicate not only for the special needs of hunting or communicating across walls, but also to promote the exchange of ideas. In recent decades, the research of sign language, especially L'ASL (American Language Sign) proves the complexity of sign language. Similar to any kind of spoken language, infinite utterances can also be produced using finite symbols and rules. It has been observed that normal children whose parents are deaf-mute have to learn sign language to communicate with their parents in addition to learning spoken language. From the time they learn the first word to the appearance of language rules, spoken language and sign language are completely parallel, so from In terms of communication function, sign language is not weaker than speech.

3. When it comes to sign language, we have to talk about orangutans. Even if their vocal structure does not have the function of speech, and they can’t learn human sign language at all, experiments have been done in the former Soviet Union and the United States. Orangutans can only master a limited number of sign language symbols. They are very smart, but they can't learn human language at all, no matter speech or sign language. From this point of view, language has an important relationship with human cognitive ability, which can be said to be unique to human beings. Speech plays a huge role in human beings today, because only human beings can use limited rules to form countless different discourses, so that people can express endless thoughts with precision.

To sum up, the main reason why the language system is mainly used instead of sign language is that sign language symbols are different from verbal symbols, and each symbol is made on the premise of consciousness. It is easier for a 3-year-old to have regular speech than to teach sign language regular expressions. In addition, there is another reason that the sign language system of the deaf was not created until the 17th century. This ancient language system can express any language written in letters, but it is not linear and has been eliminated. As for why the sign language symbol system was formed so late, it may be because the number of deaf people is small after all, and the variable basis is not enough.