For anyone looking to sound more Downton Abbey than Gossip Girl (and who rues the day when Americans lost their British accents), Patricia Fletcher has a few pointers for you.
Fletcher, a dialect coach and author of Classically Speaking: Dialect for Actors, spoke with Business Insider about the methods behind mastering a proper British accent, which largely comes down to rhythm.
According to Fletcher, those who speak in neutral American—which is traditionally accepted to mean those “General American” accents heard in the Midwest or West or on news broadcasts—tend to sit on E sounds whereas our British counterparts are more terse. A word such as really, for example, is typically pronounced by Americans as "reel-lee," while the word sounds much more succinct when coming from a Brit: "real-ly."
There's also the matter of how much speakers are willing to "reveal," according to Fletcher. When Americans enunciate their A-E-I-O-Us, their lips are a bit more lax and expressive. Comparatively, speakers across the pond are a bit more reserved with their mouth movements. "Think of our phrase, that the British have a 'stiff upper lip,'" says Fletcher. "[Americans] reveal our emotions a lot through those vowel sounds."
Keep in mind, however, that the British accent Fletcher is talking about is the more traditional accent you hear in most movies and TV shows. But there are plenty of other regional British accents you can attempt to replicate.
The famously recognized cockney accent—most impressively pulled off by Audrey Hepburn in My Fair Lady and not-so-impressively by others—is typically heard resounding through the streets of East London; head to Liverpool, and you’ll hear a bit of "Scouse," or the accent that was birthed from generations of Welsh and Irish settling in the area (if you really want to get a taste of a Scouse accent, listen to The Beatles).
No matter which accent you’re trying to nail, Fletcher advises to try and avoid letting your native intonations sneak in. You can watch the full video here, and then try out your own best imitation of Maggie Smith's Dowager Countess of Grantham.