what's the differences face-to-face talk and chat via online voice?
I can talk well face to face with a native english speaker,but i am always not good command of chat via internet, who can give me some suggestions?

Question

Answer

In my opinion "face-to-face talk"means that when you talk to other people you two are sitting together(in a house) 
 But "chat via online voice"means that you two arenot in one place.You comunicate with others via internet not in person.

Answer

When you talk face-to-face in a language that you are learning, is very useful seeing the lips of your partner to understand better. In the online chat, you only have the sound, and is a litle bit dificult sometimes guess correctly what your partner is saying.

Cheers