Nobody knows exactly how many ... there are
languages
All over the world, people who ... the ability to see
lack
Sign language is... to people who can't hear
invaluable
Gestures of anger or..., a sign of welcome
disapproval
There were no astronauts in ...
Ancient Greece
The message we communicate and the way we...
transmit
When languages have a common ...
ancestor
Another type of code, which is called...
Morse code
Unlike Braile and Morse code, sign language is a true...
language
There are many possible answers to this ...
question
These languages are ... into families
grouped
... dots on a surface ... them to fell each letter.
Raised/Enable
These include ... with an arm or hand
beckoning