No. Sign languages use conventional signs, which means that everyone has to be learned to understand it (similar to the words of a phonic language). The meaning of the sign is not evident from its shape. A sign that resembles a military salute refers, for example, to a bath in PJM, which the hearing person would never have imagined.
Also, signs with the same form can have completely different meanings in different sign languages, for example the Deaf sign in the Czech sign language PJM has the meaning of HORSE and the sign KNOWLEDGE with PJM is BOY in the German sign language.
Can sign language be written? Yes, even if it’s not easy. One of the basic distinguishing characteristics of the communication of signs is its three-dimensional character. This means that the signs are located in space and can move within it. The flashing hand can also show a different mark with each hand at the same time.
In speech communication, sentences are one-dimensional sequences of words made up of sounds. A human being is unable to utter two different sounds at the same time and therefore cannot utter two words at the same time. As a result, phonic language phrases are as easy to write as letter strings. In sign languages, this is much more difficult. Nowadays, the simplest solution is to record videos.