'Ayin, a Hebrew letter, is one of the strangest letters known to man. It is pronounced in the back of the throat as a guttaral stop. It is shaped like a two-tailed
loop. But more importantly, it is a unique social-linguistic phenomenon: it is the only letter which should not be pronounced correctly in order to prove that one is of a higher social class. (sort of the opposite of the BBC English "R".)
'Ayin is actually an ugly, jarring sound to the Latin or English trained ear - it sounds like a gulp in the middle of the letter. The double aa in Baalzebub, which is a Hebrew word, is actually an 'Ayin. (Imagine a little gulp between the B and the L). The main reason it should NOT be pronounced properly has to do with the linguistic history of Hebrew.
Essentially, Hebrew was a dead language, recreated by Eliezer Ben-Yehuda in the 19th century, as way of furthering the Zionist program. The first people to learn Hebrew were mainly educated European intelligentsia, mainly Germans and Austrians. They did not, of course, know how to pronounce a proper 'Ayin. When Hebrew was transplanted, back to Israel, its ancient country of origin, the local Arabs who learned it, as well as the Sefaradi Jews, mainly Arabic in origin, did know how to pronounce it, as 'Ayin is one of the most important letters in the Arabic alphabet. (There is even a throaty 'Ayin in Arabic, 'Ghayin, which is the true sound of the GH in Baghdad, which is really pronounced ba-throatygulp-DAD) It is the Sefardi Jews, who were mainly lower class, since the level of Jews in Arab countries generally was lower in terms of education and income, who gave a well pronounced 'Ayin it's bad reputation as lower class.
Today, most well educated Jews elide over the 'Ayin. They either stop the word for a second and go one, or just lengthen the vowel before it. People speaking Hebrew with an Arabic accent pronounce the 'Ayin, as well as the lower and working class, regardless of the country of origin, who speak the 'Ayin with a clarity that would make any ancient Biblical speaker of Hebrew proud.
I am unsure whether or not this is the only case in history of a letter whose correct pronounciation is almost certainly a guarantee of a lower than normal education or income level.