The Middle Distance

Sherlock, like most outsiders, would say it "App-a-laytch-ia". 3rd syllable has a long A, doesn't rhyme with much except the letter h (aitch!).

John, who grew up there, would say it "App-a-latch-ia." Short a in the third syllable. Rhymes with patch, snatch, catch, and Cumberbatch.

Though Sherlock has probably noticed this and done a little correcting on it. He can mimic the accent when he has to. Going native, one syllable and one rednecky habit at a time.