Yes of course we do. If we dont we are not able to understand each other. There is this one story that told that people were made to speak a different language each, (i guess god did that as a punishment in that story) and therefore nobody was able to communicate in any way with each other. Today it would be the same, just on a larger scale (with languages limited to regions), if we would not have kind of agreed to use english as a world language. I think its very important that humanity did so.