Its very own dialect
“I grew up in Stoneham, a little suburb of Boston. It's pronounced 'Stone 'em’ because Massachusetts doesn't bend to the will of 'how letters are supposed to be said.”’
Josh Gondelman (born 1985), American author, comedy writer, producer and stand-up comedian
Just ignore it
“I grew up in the Boston suburbs and inherited a stubborn New England refusal to acknowledge frigid temperatures. “
-- Josh Gondelman (comedian)