Regardless of your views on multiculturalism, I would like to pose a couple of questions to you. The questions are in relation to multiculturalism and it's impact, if any, on minority languages within a multicultural society. Personally I am more of the persuasion that immigrants should assimilate into the nation they immigrate too, but that is irrelevant. Alright, so here goes...
Let's say you live in a multicultural society and there are millions of people from different cultures and ethnic groups living together. Many of these cultures have their own languages and in a multicultural society, they can keep those languages in theory. However, society cannot realistically operate with several different languages, so a lingua franca must be found, so that different ethnic groups can communicate with one another. Of course, many people will continue to keep their language alive and often times even speak it in private with other speakers [of their language]. However, as time and generations go by, there will be fewer and fewer native speakers of said language. In a society that values assimilation or the melting pot theory, such as the United States, this isn't a problem, as the native language will live on indefinitely in their home country. The problem becomes incredibly apparent if large portions, or even the entire, planet subscribe to multiculturalism.
Now a 'solution' to this hypothetical problem comes to mind almost instantly [for me anyway], and that is that each country will have it's own language and that language will be used as the lingua franca in that country. For instance, everyone in Vietnam will speak Vietnamese in public, regardless of their native language or culture; whereas everyone in France will speak French, regardless of their native language or culture. There are several problems with this, however, as the idea of forcing immigrants to learn the language of the country they immigrate to, goes against everything multiculturalism stands for. Another problem is that we live in a global age, an age where (in this case) the English language is the lingua franca of the planet. Today virtually everyone speaks English, meaning that it would almost certainly become the lingua franca for multicultural societies, as everyone speaks it, including the native population.
Due to a single [or very few] languages coming into common societal usage and the inability of education facilities to teach every single language in existence, many of these native languages will fall into disuse. This disuse could very well result in languages very seldom being used in private [with other speakers of the language] and eventually it may no longer be passed down from generation to generation anymore. As a result of this, many languages may become endangered and possibly even extinct.
Do you believe this could prove to be a potential problem with multiculturalism? If so, how do you propose we avoid it, other than the obvious answer of abandoning multiculturalism?