Out on the campaign trail, Hillary Clinton is having a bit of difficulty with her accent, which becomes, critics say, alarmingly Southern in front of Southern audiences, particularly in front of African-American audiences, to the extent that pundits are calling it her "black-cent" and accusing her of patronising her audience.

Whether the precise accent she puts on could be described as "black" seems slightly beside the point - not all black people speak with Southern accents; Barack Obama doesn't - and the criticism in the letters pages of American newspapers is largely of the "if I were an African-American, I would be insulted" variety. YouTube clips of a speech at the First Baptist Church in Selma, Alabama show her accent slippage to be far less outrageous than the comments posted there would have you believe.

A better question is whether it is permissible, or even advisable, to change one's accent to suit one's audience. Hillary Clinton hails from Chicago, but she did live in Arkansas for 20 years when her husband was the governor. Does that entitle her to a Southern accent, if she wants one? Is the tendency to slip in and out of one dialect or another, depending on your environment, a bad thing?

Ahead of the Queen's state visit, Americans were given the advice not to affect a British accent when speaking to her, as Madonna did when she went on Parkinson. We usually disapprove of this sort of thing on the basis that it is a conscious - and excruciating - attempt to ingratiate oneself.

But those of us in possession of an accent that lies somewhere between our birthplace and our current residence (my former American accent, like Madonna's, now tosses on heavy seas just off the coast of Iceland) know that it is largely out of our control, and so unattractive that we would stop immediately if we could. The real difficulty comes not from letting your accent slide to accommodate those around you, but when you end up having to impersonate yourself every time you go home. What do they think of Hillary back in Chicago?