There are many sign languages around the world.There are three primary types in the United states alone. The answer below is ASL (i.e American sign Language, or Ameslan), which is the broadest form of sign languages in the United States of America.
Depending on your connotation, this may be translated as "Become Healthy", "Become Muscular" or "Become Thin"
See here for "Become": http://www.signingsavvy.com/sign/BECOME/743/1
See here for "Healthy": http://www.signingsavvy.com/sign/HEALTHY/3591/1
See here for "Thin" {as in a thin person}: http://www.signingsavvy.com/sign/THIN/6678/1
See here for "Muscle" http://www.signingsavvy.com/sign/MUSCLE/1887/1... This sign may be used alone to represent the word "muscular" or you may also use the "R" initial after the sign as a classifier. You would still hold the "R" in the natural space {i.e. in front of the chest} or figerspelling position {in front of the dominant hand's shoulder space.} [Note: Do not use the "-ER" or person sign to represent "Muscular", because that marker always indicates a noun (typically, but not always, a profression or person,) never an adjective.]
Sign variations: You may use the muscle or muscle + "R" sign and point to the areas you are trying to build, using the "and" hand in between each. You may sign "Muscle + Rip + 'D'"(see here: http://www.signingsavvy.com/sign/RIP/4989/1)
to mean the term "ripped", you may sign "muscle + body + build" to mean "building" or "build" bodily muscles."
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.
A sign language teacher. That's what my students call me.
You can't really say it, can you?
To sign "Are you mad at me?" in American Sign Language, you would sign: "YOU MAD ME?" while raising your eyebrows and looking concerned.
The local girls use the sign for 3 then the sign for light.
In American Sign Language (ASL), you can sign "emo" by fingerspelling the letters E-M-O.
In American Sign Language, you can sign "MOM, YOU KNOW SIGN?" by signing "MOM" and then doing the sign for "YOU," followed by the sign for "KNOW," and ending with the sign for "SIGN."