Do you want to learn a sign language?
If you are hearing and want to learn a sign language, there is a few stuff you need to know about before you start -maybe even before you chose a sign language to learn.
I want to clarify that, while I was born hard of hearing, and have several HoH family members myself, I've only started learning my country's sign language a few years ago. I've, nevertheless, been around too many hearing folks that have expressed a desire to learn sign language to know what they always get wrong. So, from your local hard of hearing folk that is tired of hearing folks being not educated enough:
Sign languages are languages. They have grammar, morphology, and all the complexity and history of a language.
Sign languages aren't universal, that is: there is not only one sign language that is used by every person that knows how to sign. While the number is not known exactly, there are around 300 sign languages in use around the world nowadays.
On the same note, there is not such a thing as "South America's sign language" or "Latinoamerica's sign language". Neither there is an "Africa's sign language". Different countries of South America and Africa have their own sign language.
Sign language can and have linguistic variations. Like any other language, they are not monoliths. Don't treat them like that.
Those "exaggerated" facial expressions you see D/deaf people make as they sign? More often than not it is part of the sign language grammar
If you are learning a sign language, you will have to learn Deaf culture, even if you are learning it for your mute friend, or alike. This is mostly because there is a lot of things you won't understand otherwise, to be respectful and because most hearing people don't know sign language anyway. I know there are mute, autistic, and trans folks that want to learn sign language for a variety of reasons and don't want anything to do with D/deaf and HoH folks. While there is nothing wrong with wanting to learn a SL to hide your voice or be able to communicate, know that you will not be able to detach yourself from the Deaf community or deaf folks, as your primary source of communication in sign language would be deaf and HoH folks that sign.
On a similar note, not all deaf and HoH folks sign. Some sign and speak, others only speak, and others only sign. That is up to the individual, and one is not lesser than the other.
Blind folks, as well as amputees, can and do sign too
Most of the songs translated to sign languages by hearing folks are wrong. I know a lot of people use them to study or practice, but unless you are advanced enough to spot mistakes, or know by a fact that the translation/ interpretation was made by a D/deaf or HoH folk that signs, or a professional interpreter, stay away from it. The Deaf community had spoken about other issues with hearing people interpreting songs at length before, you can look it up if you want to learn more.
Don't go fishing for a sign name, and stop treating it like some sort of trophy to show off. Is incredibly rude and irritating.
Deaf culture is not a monolith, it changes from country to country, and in some cases, from race to race. Learn the Deaf culture from the sign language you are learning, and don't judge or politicize the Deaf culture from another one
And most importantly: Deaf and HoH people don't own you anything. Nor congratulations or gratefulness for learning a sign language, nor teaching you about deaf culture. Not even teaching you signs or how to sign at all
Deaf and HoH folks are always welcome to add more!