I wonder if there is a word for someone from an upper-class background who deliberately adopts some lower-class mannerisms (such as using words associated with lower social status or putting on an accent).
In the UK this is often called 'Mockney' from mock+Cockney.
Linguistically, Cockney English refers to the accent or dialect of English traditionally spoken by working-class Londoners. In recent years, many aspects of Cockney English have become part of general South East English speech, producing a variant known as Estuary English.
Several British politicians are guilty of this, in feeble attempts to make themselves more appealing to the working classes.Here is Conservative MP George Osborne at it, as recorded by The Telegraph newspaper.
Ex-Prime Minister Tony Blair was also guilty of it.
Certainly with regard to the accent (but with associated aspects too)- mockney:
"pronunciation of English by someone who pretends to speak like a cockney, in order to seem as if they are from a lower social class".
The result of the popularity of such style, though, is inevitably to raise the staus of the formerly "lower class", until the gesture becomes meaningless.
Such a person might be referred to as a poser or wannabe: someone who acts or dresses in ways they believe align them with a different (e.g. poorer or "lower-class") culture, thereby posing as relatable to people in that culture or even as a member of that culture.
These terms don't suggest mockery of the target culture. In fact, they describe someone who admires a culture enough to emulate it. The terms are used derisively, as such people are generally perceived as foolish.
Lame: adjective, lamer, lamest. 1. crippled or physically disabled, especially in the foot or leg so as to limp or walk with difficulty. 2. impaired or disabled through defect or injury: 3. weak; inadequate; unsatisfactory; clumsy: 4. Slang. out of touch with modern fads or trends; unsophisticated. --Ref: http://dictionary.reference.com/browse/lame