It's simple: outside of Pompei, Italy, there are mushroom-shaped buildings. In SMW2, we see Mario and Luigi being delivered to a mushroom house, and we see the bottom halves of their parents. The mushroom house is in Pompei. Later, the Mario family moved to Brooklyn, New York. Since they were from Italy, English is their second language, thus the thick, over-exaggerated accent.
Clear?
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In my dream, the world had suffered a terrible disaster. A black haze shut out the sun, and the darkness was alive with the moans and screams of wounded people.
Suddenly, a small light glowed. A candle flickered into life, symbol of hope for millions. A single tiny candle, shining in the ugly dark. I laughed, and blew it out.