I"d have to say this question is too large for a simple true or false. Language facilitates society, yes, but as Dbackers stated, language can also rip societies apart. Look at what Al-Qaida is doing to Islam, what Hitler did to Germany, what Mussolini did to Italy, there are hundreds of examples of how language can be used to tear societies apart.
In an IDEAL world perhaps language will bring people together, actually in our world it has. The dominant language of the internet is English and most of us have friends who live in parts of the world where English is not the dominant language yet, we communicate with each other. Some variation of English, it is my conjecture, will eventually become the "common" language of the entire world.
Where language can be the glue that holds society together is where a common language can present morality and law among people