Obviously the words cask, the, and of do not require additional assistance, but students always struggle with saying amontillado. Amontillado refers to a Spanish wine so it is a Spanish word and should probably be pronounced the Spanish way.
Poe, however, wrote the story for Italian characters and it is likely that his characters would use an Italian pronunciation so if you Italianize it then you won't be far off the mark. In the end it doesn't much matter. If you just wanted to substitute the word root beer you could, though it might take away from the mood of the story a little bit.