I'm French, so English isn't my mother tongue and after 10 years living in Southern California, I'm still unclear what the difference is between a cupcake and a muffin. Every time I call one of those two "a muffin", I get corrected by someone who says "Oh, that's not a muffin. It's a cupcake!" The difference in their appearance isn't relevant to me. They look pretty much the same. Why are there two different words in the English language to describe almost the same concept? Does anyone have a good explanation?