Some of the advantages of speaking are you can express enthusiasm in levels, you can have accents and you can use hand motions. On the other hand not speaking or what I'm assuming to be indirectly talking like a book some of the advantages are you have plenty of time to think of what you are to say, suppose you in a heated argument in real life. You may in the spur of the moment say something you regret, while using letters of texts it is far easier to think for at least a second before responding.
