Not so much "sign language", but certainly extensive hand signals (like a SWAT or Navy SEAL team). You guys will basically make Innuendo checks at a low DC, and with a circumstancial bonus, when performing such an action amongst each other.
"There's a beast in every man, and it stirs when you put a sword in his hand."
- Ser Jorah Mormont
"I fight... so that you don't have to."
- Templar Thomas Marshall
"I am not a warrior." "Very soon... you will be."
- Conversation between Ahmad ibn Fadlan and Herger the Joyous