Mandarin for concise brevity, but often ambiguity whether accidental or intended. English for precision. Spanish for poetry. French for philosophy (it is possible to make the most inane idea sound profound.) I don't know what German is good for (see MArk Twain's essay on that language.)*
Linguistic diversity occurs in areas where abundant resources and challenging terrain result in non-interacting pockets of population. Two of the most linguisticly diverse areas before industrialization were northern California and West Africa.
English's preponderance is largely due to the succession of one English-speaking world empire with another, England --> USA. This is the first time that has happened. Had things gone differently 60 or 70 years ago, we might all be speaking German as a second language. Instead, English has supplanted German for scientific and technical journals. Except for botany, which still accepts papers in Latin, a requirment only recently relaxed: they are beginning to accept English.
A language's suzerainty depends more on political and economic factors, IMO. If the imminent collapse of technological civilization due to climate change occurs, populations will become fragmented, and so will spoken language. English to be like Latin, the written language of the educated? Already 'Strines (Australians) are hard to understand unless they talk slowly. But maybe there is something to ease of pronunciation; in one international Dutch company's headquarters in Holland, if a native Dutch speaker had a sore throat he would switch to English. Less painful to pronounce. Achhhh.
China may offer an example of what is to come if our civilization remains intact: there are over 60 recognized languages, and more undocumented. Almost all understand Mandarin (and now some English) but each city has its own dialect or slang, so much so that normal speech in Chengdu, or Hunan south of Changsha will not be understood by a Mandarin speaker from the northeast. In Shanghai, they speak Wu, as different from Mandarin as French from Spanish. Various mutually incomprehensible Wu dialects are spoken south to Fujian,where Min (related to Vietnamese) and Chaozhou are spoken, then Guangzhou, where you hear Cantonese, the second most widely spoken language in China. West in Hunan, there are four dialects of Xiang, old Xiang retaining glottal stops, tones and other features of Middle Chinese.
"Li siaow Yingyu bu?" instead of "
Ni shao Yingyu ma?" ("Do you speak English?" a most useful phrase any other language.)
My point is this: other languages will survive if their native speakers hold on to them, which they will do if there are enough of them, and they continue to speak their tongue at home with their children.
Vive la langue française.* "Any language that calls a 'glove' a 'hand-shoe' displays a singular lack of imagination." -- Mark Twain
Edited by maxwatt, 23 December 2012 - 08:22 PM.