Complex sentence: Although identical in appearance, Jeckle spoke with an English accent, while Heckle spoke with a New York dialect--although the characters seldom referred to each other by name, leading to some confusion.
Split into simpler sentences: Although identical in appearance, Jeckle spoke with an English accent, while Heckle spoke with a New York dialect. However, the characters seldom referred to each other by name, leading to some confusion.