Le Snob

Episode two of The Story of English pointed out that after the Norman conquest of England in 1066, speaking French and later English influenced by French became a sign of sophistication. The languages of the original inhabitants of Britain as well as those of the Anglo-Saxon invaders became unsophisticated and harsh-sounding, while French became the language of the royalty and upper class. Poor serfs were ignorant of the new imposed foreign vocabulary, starting a tradition of having French as a sign of sophistication in the English language (MacNeil, McCrum, Cran 1:40). Throughout history Latin and French words have remained as the sophisticated way of speaking English for a lot of people's points of view. Although knowing French is not actually sophistication (it's just another language), the Western culture has seen this language as a cultured and elegant one. Simply by listening to different British accents you can see that the classy ones, or posh, have both an influence from French in lexicon and resonance, while the perceived as unsophisticated, like the cockney accent, has a gruff sound that resembles Germanic roots. Ever since the Battle of Hastings, French has remained as an attractive sound for English speakers and it's clear to see today.

After a French immersion summer program, I can witness that for the American eye, learning French means culture. I don't mean that people who learn French are sophisticated, but that the Americans that I met mostly saw their summer abroad as a part of their sophistication. Despite dislike between countries, many prestigious British boarding schools force students to learn French as part of their "posh" formation. The snobbiest people I've met have let me see that French is a part of way of speaking. For any culinary term to sound elegant and chic, it usually has French words (chic, hors d'oeuvres, à la carte, carte du jour, foie gras, fleur de del, cordon bleu, mousse, crêpes, crème, bon appétit). Although most of these terms have literal translations to English, like crème to creme, it is accepted and widely done to use the French alternative to make it more elegant, making many of these words now actual English words. If you want to socialize in a snobby way, you can ask someone for a rendezvous or a soirée and then ask them to RSVP (respondez s'il vous plait). Ever since the Norman conquest of England, among with other historical factors, French-based words in English have held some type of social prestige. 

Source:

"The Mother Tongue." The Story of English. Wrti. Robert MacNeil, Robert McCrum and William Cran. MacNeil-Lehrer Productions and BBC, 1986. Youtube.