Don't all languages come into existence to facilitate communication? I'm not sure why sign language grammar systems would be considered more natural than spoken language grammar systems. Can you give some examples?

Well I done't know to much about Sign language grammar but I do think that a visual language is easier to pick up from scratch. What I mean if I told you that you would have to some kids something in a spoken language that terrifies you woulwould you be able to somewhat communicate with them? Well I had somethin years offer experience judo and jiu jutsu and was then suddenly invited to come and help at the world deaf day the next week. Oke truth be told you there was a guy who was deaf and I had tried to communicate with him every now and then when the translator didnt pay attention. But at the event when the translator wasnt there to translate I tried to come up with my own versions offer what I thought they might understand. Sometimes they didnt sometimes they did understand me event though I had no knowledge or experience what so ever. If you had to communicate with Russian, Chinese or Swahili people tomorrow do you think you would be able to communicate with them. Anyone out thereally who wants to try and teach me Dutch sign language.

Interesante as Yader said that.

I am BSL native signer and I often wonder which spoken or visual language has more natural in fluency.

In my experience, the feeling the signer need to express must be coming from her/his heart & I do not know if the sound the speaker need to respond from her/his mind or heart. That is what makes interesting me but I could still be disagreed by anyone.

Yes, I am Psychologist and body language is very important too, even to keep a reciprocal conversation.

Interesante!!! :-)