How well do we read body language? Does it vary with age, gender, personality, etc?

Does it have an impact on learning a new language?
Total Physical Response (TPR) vs. an audio-only online class

Accusing glance
She met his accusing glance, feeling guilt she could not explain.
The board members exchanged accusing glances as the report was read.

Question

How well do we read body language? Does it vary with age, gender, personality, etc?

Does it have an impact on learning a new language? 
Total Physical Response (TPR) vs. an audio-only online class

Accusing glance
She met his accusing glance, feeling guilt she could not explain.
The board members exchanged accusing glances as the report was read.

Answer

Yes, body language is the most ancestral form of communication. Even animals understand it, better than noises. Your appearance is like a picture that paints a thousand words.