This is interesting:
The "gay accent" or varies from person to person, but it's usually characterized by lisping, hypercorrection, and lilting, "feminine" pitch and vowel length. There are also vocabulary differences, so you can even think of it as a "gay dialect"... or, rather, a "gay sociolect," since it's not tied to a geographical area. Most speakers are able to "code switch" - in essence, they can turn it on and off. It's a marker of identity. Lots of cultural groups have sociolects that they use to show membership in a group - think of BEV (Black English Vernacular aka Ebonics), or "Valley Girl" speech, or the l337speak used online.
As far as history, some linguists say that the gay accent was influenced by the California accent, since California was the heart of the early gay rights movement in the US. But a "gay dialect" actually goes back a lot farther than that! The British dialect of Polari might go back to the 16th century. Polari actually sounds a bit like what we'd call a "gay accent" today, and it has its roots in a combination of Roma argot, Cockney rhymbing slang, and exaggerated, singsong theatrical speech (think the old Punch and Judy puppet shows). Polari almost completely died out in the 1960s and 70s, though, as it started to be seen as a negative stereotype. But quite a lot of Polari words are still in use (such as "drag," which comes from the Romani word "indraka," or "skirt.")
