Does teaching babies to sign before speaking suggest anything about the emergence of human language?

There is a popular movement which encourages parents to teach their babies to sign as early as possible. Proponents of this movement suggest that babies are able to learn and communicate in sign language well before they are able to communicate using spoken words. .

I would like to self-learn sign language, can anyone suggest some ‘lesson plan’ or something? Even tips?

I have 1 huge asl book, a ‘signing everyday phrases’ book, a gallaudet survival guide to signing, and ‘For hearing people only’, even tho im HI. Can anyone suggest some sort of lesson plan for signing? I’d like to learn SIGNED ENLISH/ Thanks. .