Back to sign language, and it's probably a surprise to a lot of people that American sign language is hugely different also to *American* spoken English!
The grammatical structures are quite separate, if anything it's more akin to spoken Japanese than English.
This is an important point, because when it comes to learning American sign language, it is *not* the same as miming the spoken word.
Any course or book that teaches you this way is leading you down the wrong path, and will leave you all at sea if you try to sign with someone who has been taught properly.
This is another reason why, when looking for a course to choose, that you pick a course that has good testimonials, that has samples you can try, and let's you find out all about the course in advance, with a solid money back guarantee.