We all know that English has become the world’s lingua franca (now that’s a phrase that needs updating!). But sometimes having English as a common language can be a bad thing, or at least a problematic thing.
For example, as Yann Foucault has pointed out, translation can help expand both the target language and whatever topic the text is on.
Also, using tongues other than English can create a sense of regional identity. Read this piece on using English in the Nordic countries. In the Nordic region, is it better to use English as the common tongue or to insist on interpretation and translation?