The very first chocolate wasn’t in fact a solid chocolate bar as we know it now. It was a hot drink produced from the beans of cacao tree by the Mayans and Aztecs. The name of the drink was xocoatl (shock-wa-tull). The Spanish conquistadors returned home with the exotic drink in 1528 and called it chocolate (cho-co-lah-tay). The drink became very popular among Spanish aristocracy which used to party heavily all around European continent. That is how it was introduced to French nobility during a royal wedding in 1615 where they called it chocolate (sho-co-lah). Very soon this mysterious and fancy drink crosses the Channel and was lost in hundreds of British, Irish and Scottish accents. They called it chocolate, jocolatte, jacolatte and even chockelet.
In fact the chocolate pronunciation as we know it had to wait until firs chocolate arrived to the United States. Only than people started to pronounce it CHOCOLAT (chock-lit).