Bitcoin is becoming more popular everyday. More people are getting to now what Bitcoin is. I would say that, as a result of this, Bitcoin is becoming a global currency.
Well, up to a global currency Bitcoin is still far. But many countries have already started using it. I hope it will develop
Since there is no formal definition of what is a global currency I would call bitcoin as global currency because it is already accepted in most countries and for me that is a sign that the world already know bitcoin. Although it is not yet widely used but in the future it will become more popular.