Text messaging is a much more prominent mobile application than voice in Asia and Europe than the U.S. Why is that? It has to do with how people text message and where they use it. Text messaging needs hands to input and people often do that while they are on the move.
As a nation of automobiles, most of American commute in their cars, and most often they drive alone. Although a few manage to do aerobatic tasks while driving (certainly not recommended), most people do not the physical skills to text message while driving.
According to the Labor Statistical Survey on American Time Use, the average American spend 10 minutes per day on mail, email and phone call. How much that can be curved out for text messaging? Not very much apparently.
The commuting options also explain why text messaging are more popular in Asia and Europe. It's because most people use public transportation and can free their hands to text message. Text messaging is also more private than talking aloud to overcome the noises in public transit.