Hillaire Belloc made the interesting claim that it was thanks to Latin that the various European languages were able to develop so freely: you could always communicate in Latin when you traveled. He also noted that the various lingua francas since Latin was lost have tended to suffer from becoming the world language. Looking at English today one is hard pressed to disagree.
How has English suffered from becoming the world language? I don't see it.
I often see something that could inspire this argument when I travel, people have made a native and English version of a sign or some sort of text. The English is riddled with laughable errors - why? Because everyone knows English and why would you ever hire a translator, just get Jules down in accounting to do it, he's great! (only it turns out Jules is not great)
I will now, at the end of my explanation of how I think someone might want to make the argument, explain that I myself am not a supporter of the argument (nor do I know if this is indeed what Belloc supposed) and hope not to get one of those responses telling me how wrong I am in believing what I do not have a particular belief in.