You can't speak sign language but you can "sign".
In American Sign Language, you can sign "WHEN YOU BORN?" to ask someone when they were born.
To indicate that you're okay in American Sign Language, make the sign by touching your fingertips to your chin and then moving your hand away from your face. This gesture signifies that all is well.
To sign "Are you happy?" in American Sign Language, you would sign: YOU HAPPY? with raised eyebrows.
To say how are you in sign language you open your arms like you are pushing forward while swimming then sign R and then point at them.
You sign it.
You make an I in sign language and then point to your head and then nod.
In American Sign Language (ASL), you can sign "I know" by pointing to your head with your index finger.
Well, you have to spell it out. (M-I-C-H-A-E-L etc.)
You can't really say it, can you?
A sign language teacher. That's what my students call me.
To sign "Are you mad at me?" in American Sign Language, you would sign: "YOU MAD ME?" while raising your eyebrows and looking concerned.