good question, you can't.
In American Sign Language (ASL), you can sign "I need talk you something."
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 sign "Are you happy?" in American Sign Language, you would sign: YOU HAPPY? with raised eyebrows.
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 need talk you something."
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 sign "Are you happy?" in American Sign Language, you would sign: YOU HAPPY? with raised eyebrows.
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.
With your use of the term "mum" I take it you're not American. Each country has its own sign language. If I give you the signs for "dad" and "mum" in American Sign Language it wouldn't be correct if you were to use them in England. If you were in England you would need the signs from British Sign Language (BSL). Resubmit your question specifying which country's sign language you need.
You can't really say it, can you?
A sign language teacher. That's what my students call me.
In American Sign Language (ASL), you can sign "emo" by fingerspelling the letters E-M-O.
To sign "Are you mad at me?" in American Sign Language, you would sign: "YOU MAD ME?" while raising your eyebrows and looking concerned.