Orally counting to five is less important than taking five cans of pop to fill the machine. Teaching eye contact for the sake of eye contact is a waste of time and offensive to both parties. I don't have to see you to hear you. If a student uses sign language or specific gestures to communicate, make up a sign language vocabulary book that they can take to their next classroom or setting. Students may slightly change signs from the strict ASL or SEE description, so that someone else familiar with sign languages misinterprets the sign.
Sign language can be useful, but only with other people who understand sign.
Using sign language at Taco Generica to order a burrito, a coke and an ice cream cone might pose difficulties.