Recently a language died out (
http://news.bbc.co.uk/2/hi/south_asia/8498534.stm) and it's said to be a loss to society. I've heard similar views expressed before, mostly with people saying how bad it is that of the 4000 or so languages that exist, the vast majority are endangered and becoming extinct, usually because the only people speaking them are very old. Most will be lost without ever being recorded.
Is the loss of these languages really a loss though? They are certainly a cultural heritage, but do they actually have any value? Most of these languages are unknown and whether they are lost or not will make almost no difference to anyone. In fact the purpose of a language is to allow people to communicate, as such there is really no need for more than one language. Is it really worth struggling to record and preserve thousands of languages that serve no purpose?